Document and Entity Information [Abstract] Document and entity information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Goodwill and Intangible Assets Disclosure [Abstract] Schedule of intangible assets and goodwill Schedule of Intangible Assets and Goodwill [Table Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Income Tax [Abstract] Income Tax [Abstract] Income Tax Examination, Penalties and Interest Expense Income Tax Examination, Penalties and Interest Expense Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer Relationships [Member] Customer Relationships [Member] Trademarks [Member] Trademarks [Member] Trade secrets [Member] Trade Secrets [Member] Carrier relationships [Member] Carrier Relationships [Member] Carrier relationships. Other finite-life intangible assets [Member] Other Finite Life Intangible Assets [Member] Other finite-life intangible assets. Summary of Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Finite-life intangible assets, Gross Carrying Amount Finite-Lived Intangible Assets, Gross Finite-life intangible assets, Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Total finite-life intangible assets, Net Finite-Lived Intangible Assets, Net Indefinite-life intangible assets gross Indefinite Lived Intangible Assets Excluding Goodwill Gross Indefinite-life intangible assets gross. Indefinite-life intangible assets, Accumulated Amortization Indefinite Intangible Assets Accumulated Amortization Indefinite-life intangible assets amortization. Indefinite-life intangible assets Indefinite-Lived Intangible Assets (Excluding Goodwill) Total Intangible Assets, Gross Intangible Assets, Gross (Excluding Goodwill) Intangible assets, Accumulated Amortization Intangible Assets Accumulated Amortization Intangible assets accumulated amortization. Total intangible assets, net Intangible Assets, Net (Excluding Goodwill) Equity [Abstract] Accumulated Other Comprehensive Loss Comprehensive Income (Loss) Note [Text Block] Basis of Presentation [Abstract] Basis of Presentation [Abstract] Fiscal Period Duration Fiscal Period Duration Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Stock Options [Member] Employee Stock Option [Member] Restricted Stock Units [Member] Restricted Stock Units (RSUs) [Member] Performance-Based Restricted Stock [Member] Performance Shares [Member] Restricted Stock Awards [Member] Restricted Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Compensation expense Allocated Share-based Compensation Expense Range of restricted stock to be issued minimum (shares) Range of Restricted Stock to be Issued Minimum Range of restricted stock to be issued minimum. Range of restricted stock to be issued maximum (shares) Range of Restricted Stock to be Issued Maximum Range of restricted stock to be issued maximum. Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Restricted stock awards outstanding (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Number Restricted stock awards, weighted average exercise price (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Exercise Price Stock options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Weighted average exercise price (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Share Repurchase Program [Abstract] Share Repurchase Program [Abstract] Stock Repurchase Program, Number of Shares Authorized to be Repurchased Stock Repurchase Program, Number of Shares Authorized to be Repurchased Stock Repurchased During Period, Shares Stock Repurchased During Period, Shares Stock Repurchased During Period, Value Stock Repurchased During Period, Value Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Earnings Per Share [Abstract] Earnings per Share Earnings Per Share [Text Block] Summary of Accumulated other comprehensive loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Income Statement [Abstract] Sales Revenue, Net Cost of sales Cost of Goods and Services Sold Gross profit Gross Profit Selling, general and administrative expenses Selling, General and Administrative Expense Operating income Operating Income (Loss) Interest (expense) income, net Interest Income (Expense), Net Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax provision Income Tax Expense (Benefit) Net income Net Income (Loss) Attributable to Parent Weighted average number of shares outstanding - basic Weighted Average Number of Shares Outstanding, Basic Weighted average number of shares outstanding - diluted Weighted Average Number of Shares Outstanding, Diluted Basic earnings per share Earnings Per Share, Basic [Abstract] Basic earnings per share Earnings Per Share, Basic Diluted earnings per share Earnings Per Share, Diluted [Abstract] Diluted earnings per share Earnings Per Share, Diluted Cash dividends declared per common share Common Stock, Dividends, Per Share, Declared Goodwill Goodwill Statement of Financial Position [Abstract] Allowance for doubtful accounts, trade receivables Allowance for Doubtful Accounts Receivable, Current Intangible assets accumulated amortization Shares authorized Common Stock, Shares Authorized Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Common Stock, Shares, Issued Common Stock, Shares, Issued Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Commitments and Contingencies Disclosure [Abstract] Litigation, Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Business Combinations [Abstract] Schedule of Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Schedule of Finite-Lived Intangible Assets Acquired Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Cash and Cash Equivalents [Abstract] Cash and Cash Equivalents and Investments Cash and Cash Equivalents Disclosure [Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Customer Relationships [Member] Trade Names [Member] Trade Names [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Davis Supply Inc. [Member] Davis Supply Inc. [Member] Davis Supply Inc. [Member] The Dumont Company, Inc. TheDumontCompany,Inc. [Member] The Dumont Company, Inc. [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Payments to Acquire Businesses, Net of Cash Acquired Payments to Acquire Businesses, Net of Cash Acquired Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period Business Acquisition, Revenue Reported by Acquired Entity for Last Annual Period Preliminary Value of Goodwill and Intangible Assets Acquired Preliminary Value of Goodwill and Intangible Assets Acquired Preliminary Value of Goodwill and Intangible Assets Acquired Number of operating locations acquired Number of operating locations acquired Number of operating locations acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract] Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract] Accounts receivable Accounts Receivable Acquired Accounts Receivable Acquired Inventory Inventory Acquired Inventory Acquired Other assets Other Assets Acquired Other Assets Acquired Property, plant, and equipment Property, Plant, and Equipment Acquired Property, Plant, and Equipment Acquired Intangible assets Finite-lived Intangible Assets Acquired Current liabilities Liabilities Assumed Net assets acquired Net Assets Acquired and Liabilities Assumed Net Assets Acquired and Liabilities Assumed Goodwill Goodwill, Acquired During Period Total purchase price Payments to Acquire Businesses, Gross Organization, Consolidation and Presentation of Financial Statements [Abstract] Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Inventory Disclosure [Abstract] Summary of Inventories Schedule of Inventory, Current [Table Text Block] Business Combination Disclosure [Text Block] Business Combination Disclosure [Text Block] Summary of Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain (loss) on: Other Comprehensive Income (Loss), Net of Tax [Abstract] Available-for-sale investments Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Post-retirement plan liability Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Schedule of Cash and Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Cash and Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Maturities period of certificates of deposit minimum Maturities Period of Certificates of Deposit Minimum Maturities period of certificates of deposit and municipal bonds minimum Maturities period of certificates of deposit maximum Maturities Period of Certificates of Deposit Maximum Maturities period of certificates of deposit maximum. Available-for-sale Securities, Current Available-for-sale Securities, Current Available-for-sale Securities, Noncurrent Available-for-sale Securities, Noncurrent Finished goods (LIFO basis) LIFO Inventory Amount Increase (decrease) in LIFO reserve Inventory, LIFO Reserve, Period Charge Shares or stock options excluded from the calculation of diluted EPS Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Summary of financial assets and liabilities measured at fair value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Share Repurchase Program Stockholders' Equity Note Disclosure [Text Block] Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Business Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Industrial [Member] Industrial [Member] Industrial. Water Treatment [Member] Water Treatment [Member] Water treatment. Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Sales Gross profit Selling, general and administrative expenses Operating income Summary of Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] ASSETS Assets [Abstract] CURRENT ASSETS: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Investments available-for-sale Marketable Securities Trade receivables — less allowance for doubtful accounts: $402 as of September 27, 2015 and $445 as of March 29, 2015 Accounts Receivable, Net, Current Inventories Inventory, Net Income taxes receivable Income Taxes Receivable, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current PROPERTY, PLANT, AND EQUIPMENT: Property, Plant and Equipment [Abstract] PROPERTY, PLANT, AND EQUIPMENT: Property, Plant and Equipment, Gross Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Net property, plant, and equipment Property, Plant and Equipment, Net Goodwill Intangible assets — less accumulated amortization: $4,533 as of September 27, 2015 and $3,933 as of March 29, 2015 Long-term investments available for sale Long-term Investments Other Other Assets, Noncurrent Total other assets Other Assets Total assets Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity [Abstract] CURRENT LIABILITIES: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Dividends payable Dividends Payable, Current Accrued payroll and employee benefits Employee-related Liabilities, Current Deferred income taxes Deferred Tax Liabilities, Net, Current Income tax payable Accrued Income Taxes, Current Other current liabilities Other Accrued Liabilities, Current Total current liabilities Liabilities, Current PENSION WITHDRAWAL LIABILITY Defined Benefit Pension Plan, Liabilities, Noncurrent OTHER LONG-TERM LIABILITIES Other Liabilities, Noncurrent DEFERRED INCOME TAXES Deferred Tax Liabilities, Net, Noncurrent Total liabilities Liabilities COMMITMENTS AND CONTINGENCIES Commitments and Contingencies SHAREHOLDERS’ EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Common stock; authorized: 30,000,000 shares of $0.05 par value; 10,478,266 and 10,564,949 shares issued and outstanding as of September 27, 2015 and March 29, 2015, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss) Total shareholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and shareholders’ equity Liabilities and Equity Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net Income Reconciliation to cash flows: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock compensation expense Share-based Compensation Loss (gain) from property disposals Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Changes in operating accounts providing (using) cash: Increase (Decrease) in Operating Capital [Abstract] Trade receivables Increase (Decrease) in Accounts Receivable Inventories Increase (Decrease) in Inventories Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Income taxes Increase (Decrease) in Income Taxes Payable Other Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of property, plant, and equipment Payments to Acquire Property, Plant, and Equipment Purchases of investments Payments to Acquire Investments Sale and maturities of investments Proceeds from Sale and Maturity of Marketable Securities Acquisition Other Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Cash dividends paid Payments of Ordinary Dividends, Common Stock New shares issued Proceeds from Stock Plans Shares surrendered for payroll taxes Payments Related to Tax Withholding for Share-based Compensation Shares repurchased Payments for Repurchase of Equity Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Cash and Cash Equivalents, Period Increase (Decrease) CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD CASH AND CASH EQUIVALENTS, END OF PERIOD SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION Supplemental Cash Flow Information [Abstract] Cash paid for income taxes Income Taxes Paid, Net Noncash investing activities - Capital expenditures in accounts payable Capital Expenditures Incurred but Not yet Paid Summary of performance-based restricted stock units Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Number of reportable segments (segments) Number of Reportable Segments Intersegment sales Intersegment Sales Intersegment sales. Number of operating segments aggregated (segments) Number of Operating Segments Aggregated Number of operating segments aggregated. Number of customer representing 10 percent or more of revenue (customers) Entity Wide Revenue Major Customer Number of Customers Entity wide revenue major customer number of customers. Summary of basic and diluted EPS Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Cash [Member] Cash [Member] Certificates of deposit [Member] Certificates of Deposit [Member] Municipal bonds [Member] Municipal Bonds [Member] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Total [Member] Estimate of Fair Value Measurement [Member] Summary of financial assets and liabilities measured at fair value Cash, Cash Equivalents, and Short-term Investments [Abstract] Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Cash/Certificates of deposit/Money market securities Cash and Cash Equivalents, Fair Value Disclosure Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Inventories Inventory Disclosure [Text Block] Statement of Comprehensive Income [Abstract] Net income Other comprehensive income (loss), net of tax: Unrealized gain (loss) on available-for-sale investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Total comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Summary of basic and diluted EPS Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted-average common shares outstanding-basic (shares) Dilutive impact of stock options, performance units, and restricted stock (shares) Weighted Average Number Diluted Shares Outstanding Adjustment Weighted-average common shares outstanding-diluted (shares) Summary of Inventories Inventory, Net [Abstract] Inventory (FIFO basis) Inventory, Finished Goods, Gross LIFO reserve Inventory, LIFO Reserve Net inventory Restricted stock activity Restricted Stock Activity [Abstract] Restricted stock activity. Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Unvested at beginning of period (Shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (Shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (Shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Unvested at end of period (Shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Beginning Balance, Weighted average grant date fair value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted, Weighted average grant date fair value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested, Weighted average grant date fair value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Ending Balance, Weighted average grant date fair value (usd per share)