Net Income (Loss) Per Share - Computation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income (loss) attributed to PAE Incorporated	$ 15,290	$ (49,809)	$ (34,459)
Denominator:
Basic weighted average shares (in shares)	84,114,016	21,127,823	21,127,823
Diluted weighted average shares (in shares)	85,369,328	21,127,823	21,127,823
Basic income (loss) per share (in dollars per share)	$ 0.18	$ (2.36)	$ (1.63)
Diluted income (loss) per share (in dollars per share)	$ 0.18	$ (2.36)	$ (1.63)