Significant Accounting Principles and Policies - Impact of Restatement on Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Reclassification [Line Items]
Net income	$ 12,273	$ 26,150
Other comprehensive loss:
Change in foreign currency translation adjustment, net of tax	(994)	(976)
Other, net	(1)	281
Other comprehensive loss	(995)	(695)
Comprehensive income	11,278	25,455
Comprehensive (loss) income attributed to noncontrolling interests	(1,254)	498
Comprehensive income attributed to PAE Incorporated	$ 12,532	24,957
As filed
Reclassification [Line Items]
Net income		(4,777)
Other comprehensive loss:
Change in foreign currency translation adjustment, net of tax		(976)
Other, net		281
Other comprehensive loss		(695)
Comprehensive income		(5,472)
Comprehensive (loss) income attributed to noncontrolling interests		498
Comprehensive income attributed to PAE Incorporated		(5,970)
Restatement adjustments
Reclassification [Line Items]
Net income		30,927
Other comprehensive loss:
Change in foreign currency translation adjustment, net of tax		0
Other, net		0
Other comprehensive loss		0
Comprehensive income		30,927
Comprehensive (loss) income attributed to noncontrolling interests		0
Comprehensive income attributed to PAE Incorporated		$ 30,927