Discontinued Operations - Summary of Pretax Profit (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) gain on sale of discontinued operations			$ 79,602	$ 0
(Loss) income from discontinued operations, net of tax	$ (967)	$ 2,021	76,697	4,338
Discontinued Operations, Disposed of by Sale | GS segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	0	28,868	27,737	86,809
Direct costs	0	20,532	19,494	63,531
Gross profit	0	8,336	8,243	23,278
Selling, general and administrative expenses	0	5,373	6,842	16,702
Depreciation and amortization	0	248	307	749
Income from discontinued operations	0	2,715	1,094	5,827
(Loss) gain on sale of discontinued operations	(402)	0	79,602	0
Other income (expense), net	0	8	(436)	0
(Loss) income from discontinued operations, before income taxes	(402)	2,723	80,260	5,827
Income tax expense	565	702	3,563	1,489
(Loss) income from discontinued operations, net of tax	$ (967)	$ 2,021	$ 76,697	$ 4,338