3.26.1 html 133 227 1 true 36 0 false 4 false false R1.htm 000 - Document - Document And Entity Information Sheet http://www.nwpipe.com/20260331/role/statement-document-and-entity-information Document And Entity Information Cover 1 false false R2.htm 001 - Statement - Condensed Consolidated Statements of Operations (Unaudited) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-statements-of-operations-unaudited Condensed Consolidated Statements of Operations (Unaudited) Statements 2 false false R3.htm 002 - Statement - Condensed Consolidated Statements of Comprehensive Income (Unaudited) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-statements-of-comprehensive-income-unaudited Condensed Consolidated Statements of Comprehensive Income (Unaudited) Statements 3 false false R4.htm 003 - Statement - Condensed Consolidated Balance Sheets (Current Period Unaudited) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-balance-sheets-current-period-unaudited Condensed Consolidated Balance Sheets (Current Period Unaudited) Statements 4 false false R5.htm 004 - Statement - Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-balance-sheets-current-period-unaudited-parentheticals Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) Statements 5 false false R6.htm 005 - Statement - Condensed Consolidated Statements of Stockholders' Equity (Unaudited) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-statements-of-stockholders-equity-unaudited Condensed Consolidated Statements of Stockholders' Equity (Unaudited) Statements 6 false false R7.htm 006 - Statement - Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-statements-of-stockholders-equity-unaudited-parentheticals Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) Statements 7 false false R8.htm 007 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited) Sheet http://www.nwpipe.com/20260331/role/statement-condensed-consolidated-statements-of-cash-flows-unaudited Condensed Consolidated Statements of Cash Flows (Unaudited) Statements 8 false false R9.htm 008 - Disclosure - Note 1 - Organization and Basis of Presentation Sheet http://www.nwpipe.com/20260331/role/statement-note-1-organization-and-basis-of-presentation Note 1 - Organization and Basis of Presentation Notes 9 false false R10.htm 009 - Disclosure - Note 2 - Business Combination Sheet http://www.nwpipe.com/20260331/role/statement-note-2-business-combination Note 2 - Business Combination Notes 10 false false R11.htm 010 - Disclosure - Note 3 - Inventories Sheet http://www.nwpipe.com/20260331/role/statement-note-3-inventories Note 3 - Inventories Notes 11 false false R12.htm 011 - Disclosure - Note 4 - Intangible Assets Sheet http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets- Note 4 - Intangible Assets Notes 12 false false R13.htm 012 - Disclosure - Note 5 - Fair Value Measurements Sheet http://www.nwpipe.com/20260331/role/statement-note-5-fair-value-measurements Note 5 - Fair Value Measurements Notes 13 false false R14.htm 013 - Disclosure - Note 6 - Stockholders' Equity Sheet http://www.nwpipe.com/20260331/role/statement-note-6-stockholders-equity Note 6 - Stockholders' Equity Notes 14 false false R15.htm 014 - Disclosure - Note 7 - Share-based Compensation Sheet http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation Note 7 - Share-based Compensation Notes 15 false false R16.htm 015 - Disclosure - Note 8 - Commitments and Contingencies Sheet http://www.nwpipe.com/20260331/role/statement-note-8-commitments-and-contingencies Note 8 - Commitments and Contingencies Notes 16 false false R17.htm 016 - Disclosure - Note 9 - Revenue Sheet http://www.nwpipe.com/20260331/role/statement-note-9-revenue Note 9 - Revenue Notes 17 false false R18.htm 017 - Disclosure - Note 10 - Income Taxes Sheet http://www.nwpipe.com/20260331/role/statement-note-10-income-taxes Note 10 - Income Taxes Notes 18 false false R19.htm 018 - Disclosure - Note 11 - Net Income Per Share Sheet http://www.nwpipe.com/20260331/role/statement-note-11-net-income-per-share Note 11 - Net Income Per Share Notes 19 false false R20.htm 019 - Disclosure - Note 12 - Segment Information Sheet http://www.nwpipe.com/20260331/role/statement-note-12-segment-information Note 12 - Segment Information Notes 20 false false R21.htm 020 - Disclosure - Note 13 - Recent Accounting and Reporting Developments Sheet http://www.nwpipe.com/20260331/role/statement-note-13-recent-accounting-and-reporting-developments Note 13 - Recent Accounting and Reporting Developments Notes 21 false false R22.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 22 false false R23.htm 995467 - Disclosure - Note 2 - Business Combination (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-2-business-combination-tables Note 2 - Business Combination (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-2-business-combination 23 false false R24.htm 995468 - Disclosure - Note 3 - Inventories (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-3-inventories-tables Note 3 - Inventories (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-3-inventories 24 false false R25.htm 995469 - Disclosure - Note 4 - Intangible Assets (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets-tables Note 4 - Intangible Assets (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets- 25 false false R26.htm 995470 - Disclosure - Note 5 - Fair Value Measurements (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-5-fair-value-measurements-tables Note 5 - Fair Value Measurements (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-5-fair-value-measurements 26 false false R27.htm 995471 - Disclosure - Note 7 - Share-based Compensation (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation-tables Note 7 - Share-based Compensation (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation 27 false false R28.htm 995472 - Disclosure - Note 9 - Revenue (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-9-revenue-tables Note 9 - Revenue (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-9-revenue 28 false false R29.htm 995473 - Disclosure - Note 11 - Net Income Per Share (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-11-net-income-per-share-tables Note 11 - Net Income Per Share (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-11-net-income-per-share 29 false false R30.htm 995474 - Disclosure - Note 12 - Segment Information (Tables) Sheet http://www.nwpipe.com/20260331/role/statement-note-12-segment-information-tables Note 12 - Segment Information (Tables) Tables http://www.nwpipe.com/20260331/role/statement-note-12-segment-information 30 false false R31.htm 995475 - Disclosure - Note 1 - Organization and Basis of Presentation (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-1-organization-and-basis-of-presentation-details-textual Note 1 - Organization and Basis of Presentation (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-1-organization-and-basis-of-presentation 31 false false R32.htm 995476 - Disclosure - Note 2 - Business Combination (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-2-business-combination-details-textual Note 2 - Business Combination (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-2-business-combination-tables 32 false false R33.htm 995477 - Disclosure - Note 2 - Business Combination - Recognized Assets Acquired and Liabilities Assumed (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-2-business-combination-recognized-assets-acquired-and-liabilities-assumed-details Note 2 - Business Combination - Recognized Assets Acquired and Liabilities Assumed (Details) Details 33 false false R34.htm 995478 - Disclosure - Note 2 - Business Combination - Acquired Intangible Assets (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-2-business-combination-acquired-intangible-assets-details Note 2 - Business Combination - Acquired Intangible Assets (Details) Details 34 false false R35.htm 995479 - Disclosure - Note 3 - Inventories - Components of Inventories (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-3-inventories-components-of-inventories-details Note 3 - Inventories - Components of Inventories (Details) Details 35 false false R36.htm 995480 - Disclosure - Note 4 - Intangible Assets (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets-details-textual Note 4 - Intangible Assets (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets-tables 36 false false R37.htm 995481 - Disclosure - Note 4 - Intangible Assets - Summary of Intangible Assets (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets-summary-of-intangible-assets-details Note 4 - Intangible Assets - Summary of Intangible Assets (Details) Details 37 false false R38.htm 995482 - Disclosure - Note 4 - Intangible Assets - Summary of Estimated Amortization Expense (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-4-intangible-assets-summary-of-estimated-amortization-expense-details Note 4 - Intangible Assets - Summary of Estimated Amortization Expense (Details) Details 38 false false R39.htm 995483 - Disclosure - Note 5 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-5-fair-value-measurements-assets-and-liabilities-measured-at-fair-value-on-recurring-basis-details Note 5 - Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Details 39 false false R40.htm 995484 - Disclosure - Note 6 - Stockholders' Equity (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-6-stockholders-equity-details-textual Note 6 - Stockholders' Equity (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-6-stockholders-equity 40 false false R41.htm 995485 - Disclosure - Note 7 - Share-based Compensation (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation-details-textual Note 7 - Share-based Compensation (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation-tables 41 false false R42.htm 995486 - Disclosure - Note 7 - Share-based Compensation - Share-based Compensation Expense (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation-sharebased-compensation-expense-details Note 7 - Share-based Compensation - Share-based Compensation Expense (Details) Details 42 false false R43.htm 995487 - Disclosure - Note 7 - Share-based Compensation - RSU and PSA Activity (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-7-sharebased-compensation-rsu-and-psa-activity-details Note 7 - Share-based Compensation - RSU and PSA Activity (Details) Details 43 false false R44.htm 995488 - Disclosure - Note 8 - Commitments and Contingencies (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-8-commitments-and-contingencies-details-textual Note 8 - Commitments and Contingencies (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-8-commitments-and-contingencies 44 false false R45.htm 995489 - Disclosure - Note 9 - Revenue 1 (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-9-revenue-1-details-textual Note 9 - Revenue 1 (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-9-revenue-tables 45 false false R46.htm 995490 - Disclosure - Note 9 - Revenue 2 (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-9-revenue-2-details-textual Note 9 - Revenue 2 (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-9-revenue-tables 46 false false R47.htm 995491 - Disclosure - Note 9 - Revenue - Disaggregation of Revenue (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-9-revenue-disaggregation-of-revenue-details Note 9 - Revenue - Disaggregation of Revenue (Details) Details 47 false false R48.htm 995492 - Disclosure - Note 10 - Income Taxes (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-10-income-taxes-details-textual Note 10 - Income Taxes (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-10-income-taxes 48 false false R49.htm 995493 - Disclosure - Note 11 - Net Income Per Share (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-11-net-income-per-share-details-textual Note 11 - Net Income Per Share (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-11-net-income-per-share-tables 49 false false R50.htm 995494 - Disclosure - Note 11 - Net Income per Share - Loss per Basic and Diluted Weighted Average Common Share Outstanding for Continuing and Discontinued Operations (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-11-net-income-per-share-loss-per-basic-and-diluted-weighted-average-common-share-outstanding-for-continuing-and-discontinued-operations-details Note 11 - Net Income per Share - Loss per Basic and Diluted Weighted Average Common Share Outstanding for Continuing and Discontinued Operations (Details) Details 50 false false R51.htm 995495 - Disclosure - Note 12 - Segment Information (Details Textual) Sheet http://www.nwpipe.com/20260331/role/statement-note-12-segment-information-details-textual Note 12 - Segment Information (Details Textual) Details http://www.nwpipe.com/20260331/role/statement-note-12-segment-information-tables 51 false false R52.htm 995496 - Disclosure - Note 12 - Segment Information - Information Related to the Operations of the Company's Operating Segments (Details) Sheet http://www.nwpipe.com/20260331/role/statement-note-12-segment-information-information-related-to-the-operations-of-the-companys-operating-segments-details Note 12 - Segment Information - Information Related to the Operations of the Company's Operating Segments (Details) Details 52 false false All Reports Book All Reports nwpx-20260331.xsd nwpx-20260331_cal.xml nwpx-20260331_def.xml nwpx-20260331_lab.xml nwpx-20260331_pre.xml nwpx20260331_10q.htm http://fasb.org/srt/2026 http://fasb.org/us-gaap/2026 http://xbrl.sec.gov/dei/2026 http://xbrl.sec.gov/ecd/2026 true true