Business and Organization (Policies)	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation Our accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”). Our condensed consolidated financial statements include the accounts of all wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The preparation of financial statements in accordance with GAAP requires that these Unaudited Condensed Consolidated Financial Statements and most of the disclosures in these Notes be presented on a historical basis, as of or for the current interim period ended or comparable prior period. The accompanying interim statements of the Company have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X, and the Condensed Consolidated Balance Sheet at December 31, 2024 has been derived from the audited consolidated financial statements of Custom Truck One Source, Inc. at that date. Accordingly, these interim financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments, consisting of normal recurring adjustments and disclosures necessary for a fair statement of these interim statements, have been included. The results reported in these interim statements are not necessarily indicative of the results that may be reported for the entire year or for any other periods. These interim statements should be read in conjunction with the Custom Truck One Source, Inc. audited consolidated financial statements included in the Custom Truck One Source, Inc. Annual Report on Form 10-K for the year ended December 31, 2024.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards	Recently Adopted Accounting Standards Income Taxes In December 2023, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2023-09, Income Taxes—Improvements to Income Tax Disclosures (Topic 740) (“ASU 2023-09”), which expands income tax disclosure requirements to include additional information related to the rate reconciliation of our effective tax rates to statutory rates as well as additional disaggregation of taxes paid. The amendments in the ASU also remove disclosures related to certain unrecognized tax benefits and deferred taxes. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. The amendments may be applied prospectively or retrospectively. The Company adopted ASU 2023-09 on January 1, 2025 and will include the newly required disclosures in the notes to our consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ending December 31, 2025. Recently Issued Accounting Standards Income Statement In November 2024, the FASB issued Accounting Standards Update No. 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (“ASU 2024-03”), which requires additional disclosures in the notes to financial statements, disaggregating specific expense categories within relevant income statement captions. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. We are currently assessing the impact of the requirements on our condensed consolidated financial statements and disclosures.

Business and Organization (Policies)

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Our accompanying condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (“GAAP”). Our condensed consolidated financial statements include the accounts of all wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The preparation of financial statements in accordance with GAAP requires that these Unaudited Condensed Consolidated Financial Statements and most of the disclosures in these Notes be presented on a historical basis, as of or for the current interim period ended or comparable prior period.

The accompanying interim statements of the Company have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X, and the Condensed Consolidated Balance Sheet at December 31, 2024 has been derived from the audited consolidated financial statements of Custom Truck One Source, Inc. at that date. Accordingly, these interim financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments, consisting of normal recurring adjustments and disclosures necessary for a fair statement of these interim statements, have been included. The results reported in these interim statements are not necessarily indicative of the results that may be reported for the entire year or for any other periods. These interim statements should be read in conjunction with the Custom Truck One Source, Inc. audited consolidated financial statements included in the Custom Truck One Source, Inc. Annual Report on Form 10-K for the year ended December 31, 2024.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

Recently Adopted Accounting Standards and Recently Issued Accounting Standards

Recently Adopted Accounting Standards

Income Taxes

In December 2023, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2023-09, Income Taxes—Improvements to Income Tax Disclosures (Topic 740) (“ASU 2023-09”), which expands income tax disclosure requirements to include additional information related to the rate reconciliation of our effective tax rates to statutory rates as well as additional disaggregation of taxes paid. The amendments in the ASU also remove disclosures related to certain unrecognized tax benefits and deferred taxes. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. The amendments may be applied prospectively or retrospectively. The Company adopted ASU 2023-09 on January 1, 2025 and will include the newly required disclosures in the notes to our consolidated financial statements in our Annual Report on Form 10-K for the fiscal year ending December 31, 2025.

Recently Issued Accounting Standards

Income Statement

In November 2024, the FASB issued Accounting Standards Update No. 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses (“ASU 2024-03”), which requires additional disclosures in the notes to financial statements, disaggregating specific expense categories within relevant income statement captions. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. We are currently assessing the impact of the requirements on our condensed consolidated financial statements and disclosures.