CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (18,246)	$ (27,641)	$ (49,868)	$ (77,507)
Other comprehensive income (loss):
Currency translation adjustments (CTA)	(4,095)	(7,979)	(1,715)	2,281
Reclassification of CTA to net loss	0	3,176	0	3,176
Derivative financial instruments:
Unrealized losses on derivative financial instruments	0	(189)	0	(1,367)
Derivative financial instrument (losses) gains reclassified into net loss	0	(22)	0	202
Benefit obligations:
Amortization of benefit plan benefits	(246)	(514)	(492)	(870)
Other comprehensive (loss) income	(4,341)	(5,528)	(2,207)	3,422
Total comprehensive loss	(22,587)	(33,169)	(52,075)	(74,085)
Comprehensive income attributable to non-controlling interest	105	307	259	429
Comprehensive loss attributable to stockholders	$ (22,482)	$ (32,862)	$ (51,816)	$ (73,656)