Unaudited Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (15,334)	$ 4,914	$ (13,405)	$ 7,743
Other comprehensive income, net of tax:
Pension liability adjustment, net of tax expense of$253 and net of tax benefit of $327 for the nine months ended September 30, 2016 and 2015, respectively			632	(511)
Unrealized gain on derivative instruments, net of tax expense of $334 and $301 for the three months ended September 30, 2016 and 2015, respectively, and $1,084 and $684 for the nine months ended September 30, 2016 and 2015, respectively	523	472	1,699	1,072
Other comprehensive income, net of tax	523	472	2,331	561
Comprehensive income (loss)	(14,811)	5,386	(11,074)	8,304
Less: Net income attributable to non-controlling interest	1,423	1,264	4,088	4,364
Comprehensive income (loss) attributable to Engility	$ (16,234)	$ 4,122	$ (15,162)	$ 3,940