Net Loss Per Share - Computation of Basic and Diluted Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Numerator:
Net loss attributed to PAE Incorporated	$ (4,943)	$ (5,719)
Denominator:
Weighted average shares outstanding (in shares)	59,807,549	21,127,823
Basic and diluted loss per share (in dollars per share)	$ (0.08)	$ (0.27)