CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - 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	$ (109,172)	$ (107,987)	$ (319,914)	$ (284,283)
Other Comprehensive Income (Loss), Net of Tax
Currency translation adjustments	26,843	(1,170)	(118,791)	12,963
Employee benefit plan adjustments	518	624	3,578	847
Net unrealized (losses) gains on available-for-sale security	(80)	(1,944)	115	(67)
Net unrealized gains on derivative instruments:
Unrealized holding gains	4,704	3,254	13,894	9,072
Amounts reclassified from accumulated other comprehensive loss	(3,699)	(2,492)	(6,909)	(3,251)
Net unrealized gains on derivative instruments	1,005	762	6,985	5,821
Other Comprehensive Income (Loss), Net of Tax	28,286	(1,728)	(108,113)	19,564
Comprehensive Loss	$ (80,886)	$ (109,715)	$ (428,027)	$ (264,719)