Equity - Changes in AOCI/L by Component (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Apr. 01, 2018	Jan. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 856,897	$ 987,571	$ 850,757	$ 983,465
Other comprehensive (loss) income, net of tax	(11,913)	(56,867)	(33,612)	(26,150)
Ending balance	963,802	921,432	963,802	921,432
Interest Rate Swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(22,275)	12,597	(7,770)	2,483
Change in AOCI/L before reclassifications to income	(23,085)	3,414	(35,938)	12,779
Reclassifications from AOCL/I to income	(1,630)	(321)	(3,282)	428
Other comprehensive (loss) income, net of tax	(24,715)	3,093	(39,220)	13,207
Ending balance	(46,990)	16,281	(46,990)	16,281
Defined Benefit Pension Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(5,696)	(5,805)	(5,738)	(5,861)
Change in AOCI/L before reclassifications to income	0	0	0	0
Reclassifications from AOCL/I to income	41	55	83	111
Other comprehensive (loss) income, net of tax	41	55	83	111
Ending balance	(5,655)	(5,750)	(5,655)	(5,750)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(33,595)	25,433	(26,359)	4,886
Change in AOCI/L before reclassifications to income	12,761	295	5,525	20,842
Reclassifications from AOCL/I to income	0	(60,310)	0	(60,310)
Other comprehensive (loss) income, net of tax	12,761	(60,015)	5,525	(39,468)
Ending balance	(20,834)	(34,582)	(20,834)	(34,582)
Accumulated Other Comprehensive Income (Loss), Net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(61,566)	32,225	(39,867)	1,508
Change in AOCI/L before reclassifications to income	(10,324)	3,709	(30,413)	33,621
Reclassifications from AOCL/I to income	(1,589)	(60,576)	(3,199)	(59,771)
Other comprehensive (loss) income, net of tax	(11,913)	(56,867)	(33,612)	(26,150)
Ending balance	(73,479)	(24,051)	(73,479)	(24,051)
Accumulated Earnings
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1,776,227	1,613,980	1,755,432	1,647,284
Ending balance	$ 1,879,633	$ 1,659,658	$ 1,879,633	$ 1,659,658
Accounting Standards Update 2018-02 | Interest Rate Swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Adoption Of ASU No					$ 591
Accounting Standards Update 2018-02 | Accumulated Other Comprehensive Income (Loss), Net
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Adoption Of ASU No					591	$ 591
Accounting Standards Update 2018-02 | Accumulated Earnings
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Adoption Of ASU No					$ (591)