Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Balances for Each Component of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 518,517	$ 669,465	$ 982,466	$ 1,257,455	$ 669,465	$ 1,257,455
Other comprehensive income (loss) before reclassifications	(478)		(93,683)		20,144	(57,301)
Amounts reclassified from accumulated other comprehensive income (loss)	(1,250)		8,754		(580)	15,009
Net increase (decrease) in other comprehensive income (loss)	(1,728)	21,292	(84,929)	42,637	19,564	(42,292)
Ending balance	421,337	518,517	663,971	982,466	421,337	663,971
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(837,934)	(859,226)	(739,149)	(781,786)	(859,226)	(781,786)
Net increase (decrease) in other comprehensive income (loss)	(1,728)	21,292	(84,929)	42,637
Ending balance	(839,662)	(837,934)	(824,078)	(739,149)	(839,662)	(824,078)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	16,470	11,411			11,411
Other comprehensive income (loss) before reclassifications	3,254				9,072
Amounts reclassified from accumulated other comprehensive income (loss)	(2,492)				(3,251)
Net increase (decrease) in other comprehensive income (loss)	762				5,821
Ending balance	17,232	16,470			17,232
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(21,986)	(21,098)		(21,098)
Other comprehensive income (loss) before reclassifications			17,652			12,333
Amounts reclassified from accumulated other comprehensive income (loss)			4,786			9,217
Net increase (decrease) in other comprehensive income (loss)			22,438			21,550
Ending balance			452	(21,986)		452
Available-for-Sale Security
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(4,670)	(6,547)	(2,879)	(2,799)	(6,547)	(2,799)
Other comprehensive income (loss) before reclassifications	(1,944)		(2,709)		(67)	(2,789)
Amounts reclassified from accumulated other comprehensive income (loss)	0		0		0	0
Net increase (decrease) in other comprehensive income (loss)	(1,944)		(2,709)		(67)	(2,789)
Ending balance	(6,614)	(4,670)	(5,588)	(2,879)	(6,614)	(5,588)
Defined Benefit Pension Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(142,540)	(142,763)	(141,597)	(143,213)	(142,763)	(143,213)
Other comprehensive income (loss) before reclassifications	(618)		(2,899)		(1,824)	(3,107)
Amounts reclassified from accumulated other comprehensive income (loss)	1,242		3,968		2,671	5,792
Net increase (decrease) in other comprehensive income (loss)	624		1,069		847	2,685
Ending balance	(141,916)	(142,540)	(140,528)	(141,597)	(141,916)	(140,528)
Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(707,194)	(721,327)	(572,687)	(614,676)	(721,327)	(614,676)
Other comprehensive income (loss) before reclassifications	(1,170)		(105,727)		12,963	(63,738)
Amounts reclassified from accumulated other comprehensive income (loss)	0		0		0	0
Net increase (decrease) in other comprehensive income (loss)	(1,170)		(105,727)		12,963	(63,738)
Ending balance	$ (708,364)	$ (707,194)	$ (678,414)	$ (572,687)	$ (708,364)	$ (678,414)