CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 132,513	$ 198,644	$ 416,464	$ 678,695
Costs and expenses:
Cost of operations	75,156	158,273	292,691	563,171
Selling, general and administrative expenses	35,689	35,956	107,876	120,431
Advisory fees and settlement costs	3,846	4,474	10,074	22,862
Restructuring activities	2,396	2,556	6,739	9,571
Research and development costs	1,355	828	3,927	2,281
Gain on asset disposals, net	(3)	(266)	(916)	(224)
Total costs and expenses	118,439	201,821	420,391	718,092
Operating income (loss)	14,074	(3,177)	(3,927)	(39,397)
Other (expense) income:
Interest expense	(12,203)	(29,463)	(49,776)	(67,434)
Interest income	167	112	430	872
Loss on debt extinguishment	0	0	(6,194)	(3,969)
Loss on sale of business	0	0	(108)	(3,601)
Benefit plans, net	7,328	3,571	22,314	9,072
Foreign exchange	24,963	(26,735)	22,749	(27,382)
Other – net	(276)	(255)	(3,068)	208
Total other income (expense)	19,979	(52,770)	(13,653)	(92,234)
Income (loss) before income tax (benefit) expense	34,053	(55,947)	(17,580)	(131,631)
Income tax (benefit) expense	(502)	1,043	(467)	3,560
Income (loss) from continuing operations	34,555	(56,990)	(17,113)	(135,191)
Income from discontinued operations, net of tax	0	0	1,800	694
Net income (loss)	34,555	(56,990)	(15,313)	(134,497)
Net loss attributable to non-controlling interest	169	35	407	137
Net income (loss) attributable to stockholders	$ 34,724	$ (56,955)	$ (14,906)	$ (134,360)
Basic earnings (loss) per share - continuing operations (in dollars per share)	$ 0.70	$ (1.39)	$ (0.35)	$ (5.21)
Basic earnings per share - discontinued operations (in dollars per share)	0.00	0.00	0.04	0.03
Basic earnings (loss) per share (in dollars per share)	0.70	(1.39)	(0.31)	(5.18)
Diluted earnings (loss) per share - continuing operations (in dollars per share)	0.69	(1.39)	(0.35)	(5.21)
Diluted earnings per share - discontinued operations (in dollars per share)	0.00	0.00	0.04	0.03
Diluted earnings (loss) per share (in dollars per share)	$ 0.69	$ (1.39)	$ (0.31)	$ (5.18)
Shares used in the computation of earnings (loss) per share:
Basic (in shares)	49,478	40,879	47,585	25,950
Diluted (in shares)	50,056	40,879	47,585	25,950