Unaudited Condensed Consolidated Statements of Operations - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenues	[1]	$ 290,079	$ 290,856	$ 875,507	$ 937,130
Operating expenses		207,044	220,717	631,928	694,275
Gross margin		83,035	70,139	243,579	242,855
Selling, general and administrative expenses		84,647	87,786	248,507	270,619
Restructuring and other related charges, net		228	2,047	436	4,458
Gain on revaluation of contingent consideration		0	0	0	(202)
Operating income (loss)		(1,840)	(19,694)	(5,364)	(32,020)
Interest expense, net		7,647	8,022	22,658	23,250
Loss on convertible debt embedded derivative (see Note 8)		0	0	0	24,783
Other expense, net		116	123	371	455
Income (loss) before income taxes		(9,603)	(27,839)	(28,393)	(80,508)
Less: Provision (benefit) for income taxes		(2,546)	(4,313)	(3,210)	(13,377)
Net income (loss)		$ (7,057)	$ (23,526)	$ (25,183)	$ (67,131)
Earnings (loss) per common share:
Basic (in dollars per share)		$ (0.23)	$ (0.78)	$ (0.83)	$ (2.24)
Diluted (in dollars per share)		$ (0.23)	$ (0.78)	$ (0.83)	$ (2.24)

[1] Revenues attributable to individual countries/geographic areas are based on the country of domicile of the legal entity that performs the work.