Significant Accounting Principles and Policies (Policies)	9 Months Ended
Sep. 26, 2021
Accounting Policies [Abstract]
Segment Reporting	The Company’s operations are currently organized into the following two reportable segments: •Global Mission Services (“GMS”): GMS provides infrastructure and logistics management, international logistics and stabilization support, and aircraft and vehicle readiness and sustainment support. The segment focuses on customer relationships with DoD, DoS, NASA, and other government agencies for work both in the United States and outside of the United States. •National Security Solutions (“NSS”): NSS provides counter-threat solutions, business process outsourcing, adjudication support services and full life cycle support for complex legal matters. NSS focuses on customer relationships in the areas of intelligence, defense and security, and with civilian agencies.
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”) for annual financial information. In management’s opinion, all adjustments, consisting of only normal recurring adjustments, considered necessary for a fair presentation have been included. The Company closes its books and records on the last Sunday of the calendar quarter to align its financial closing with its business process, which were on September 26, 2021 and September 27, 2020, respectively. The condensed consolidated financial statements and disclosures included herein are labeled based on that convention. This practice only affects interim periods, as the Company’s fiscal year ends on December 31. The condensed consolidated financial statements include the accounts of PAE Incorporated and subsidiaries and ventures in which the Company owns more than 50% or otherwise controls. All intercompany amounts have been eliminated in consolidation.
Use of Estimates	Use of Estimates These condensed consolidated financial statements are prepared in conformity with U.S. GAAP, which requires the use of estimates and assumptions, including assumptions to determine the fair value of acquired assets and liabilities, recoverability of long-lived assets, goodwill, valuation allowances on deferred taxes, inputs used in stock based compensation, inputs in the valuation of the warrants liability and anticipated contract costs and revenues utilized in the earnings recognition process, which affect the reported amounts in the condensed consolidated financial statements and accompanying notes. Due to the size and nature of many of the Company’s programs, the estimation of total revenues and cost at completion is subject to a wide range of variables, including assumptions for timing and risks. Actual results may differ from management’s estimates and changes in these estimates are recorded when known.
Accounting Pronouncements Adopted and Accounting Pronouncements Not Yet Adopted	Accounting Pronouncements Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in ASC 740 related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 is effective in 2021 and interim periods within that year and permits for an early adoption. The Company adopted ASU 2019-12 effective January 1, 2021. The adoption of the guidance did not have a material impact on its financial statements and related disclosures. Accounting Pronouncements Not Yet Adopted In March 2020, the FASB issued ASU 2020-04 Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by the reference rate reform. The amendments in ASU 2020-04 are effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating the impact this guidance will have on its condensed consolidated financial statements and related disclosures.
Fair Value of Financial Instruments	Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between marketplace participants at the measurement date. The valuation techniques the Company utilizes to measure the fair value of financial instruments are based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect internal market assumptions. These two types of inputs create the following fair value hierarchy: •Level 1 – Quoted prices for identical instruments in observable active markets. •Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable. •Level 3 – Significant inputs to the valuation model are unobservable and reflect the Company’s own estimates and assumptions. The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, and amounts included in other current assets and current liabilities that meet the definition of a financial instrument approximate fair value because of the short-term nature of these amounts. The carrying value of the Company’s outstanding debt obligations approximates its fair value. The fair value of long-term debt is calculated using Level 2 inputs, based on interest rates available for debt with terms and maturities similar to the Company’s 2020 Credit Agreements.The warrant liability is measured at fair value at each reporting period and changes in fair value are recorded in other income, net. The public warrants liability is measured using Level 1 inputs based on observable active markets. The private placement warrants liability is measured using Level 3 inputs using the Black-Scholes option pricing model.

Significant Accounting Principles and Policies (Policies)

9 Months Ended

Sep. 26, 2021

The Company’s operations are currently organized into the following two reportable segments:

•Global Mission Services (“GMS”): GMS provides infrastructure and logistics management, international logistics and stabilization support, and aircraft and vehicle readiness and sustainment support. The segment focuses on customer relationships with DoD, DoS, NASA, and other government agencies for work both in the United States and outside of the United States.

•National Security Solutions (“NSS”): NSS provides counter-threat solutions, business process outsourcing, adjudication support services and full life cycle support for complex legal matters. NSS focuses on customer relationships in the areas of intelligence, defense and security, and with civilian agencies.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”) for annual financial information. In management’s opinion, all adjustments, consisting of only normal recurring adjustments, considered necessary for a fair presentation have been included.

The Company closes its books and records on the last Sunday of the calendar quarter to align its financial closing with its business process, which were on September 26, 2021 and September 27, 2020, respectively. The condensed consolidated financial statements and disclosures included herein are labeled based on that convention. This practice only affects interim periods, as the Company’s fiscal year ends on December 31.

The condensed consolidated financial statements include the accounts of PAE Incorporated and subsidiaries and ventures in which the Company owns more than 50% or otherwise controls. All intercompany amounts have been eliminated in consolidation.

Use of Estimates

These condensed consolidated financial statements are prepared in conformity with U.S. GAAP, which requires the use of estimates and assumptions, including assumptions to determine the fair value of acquired assets and liabilities, recoverability of long-lived assets, goodwill, valuation allowances on deferred taxes, inputs used in stock based compensation, inputs in the valuation of the warrants liability and anticipated contract costs and revenues utilized in the earnings recognition process, which affect the reported amounts in the condensed consolidated financial statements and accompanying notes. Due to the size and nature of many of the Company’s programs, the estimation of total revenues and cost at completion is subject to a wide range of variables, including assumptions for timing and risks. Actual results may differ from management’s estimates and changes in these estimates are recorded when known.

Accounting Pronouncements Adopted and Accounting Pronouncements Not Yet Adopted

Accounting Pronouncements Adopted

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in ASC 740 related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 is effective in 2021 and interim periods within that year and permits for an early adoption. The Company adopted ASU 2019-12 effective January 1, 2021. The adoption of the guidance did not have a material impact on its financial statements and related disclosures.

Accounting Pronouncements Not Yet Adopted

In March 2020, the FASB issued ASU 2020-04 Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by the reference rate reform. The amendments in ASU 2020-04 are effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating the impact this guidance will have on its condensed consolidated financial statements and related disclosures.

Fair Value of Financial Instruments

Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between marketplace participants at the measurement date. The valuation techniques the Company utilizes to measure the fair value of financial instruments are based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect internal market assumptions.

These two types of inputs create the following fair value hierarchy:

•Level 1 – Quoted prices for identical instruments in observable active markets.

•Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable.

•Level 3 – Significant inputs to the valuation model are unobservable and reflect the Company’s own estimates and assumptions.

The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, and amounts included in other current assets and current liabilities that meet the definition of a financial instrument approximate fair value because of the short-term nature of these amounts.

The carrying value of the Company’s outstanding debt obligations approximates its fair value. The fair value of long-term debt is calculated using Level 2 inputs, based on interest rates available for debt with terms and maturities similar to the Company’s 2020 Credit Agreements.The warrant liability is measured at fair value at each reporting period and changes in fair value are recorded in other income, net. The public warrants liability is measured using Level 1 inputs based on observable active markets. The private placement warrants liability is measured using Level 3 inputs using the Black-Scholes option pricing model.