Equity - Changes in AOCL/I by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 60,878
Other comprehensive (loss) income, net of tax	$ 47,673	$ 219	48,467	$ (3,382)
Ending balance	863,410		863,410
Interest Rate Swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(6,107)	(12,158)	(1,409)	(3,079)
Change in AOCL/I before reclassifications to income	9	2,076	(6,912)	(9,376)
Reclassifications from AOCL/I to income during the period	1,293	1,138	3,516	3,511
Other comprehensive (loss) income, net of tax	1,302	3,214	(3,396)	(5,865)
Ending balance	(4,805)	(8,944)	(4,805)	(8,944)
Defined Benefit Pension Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(5,700)	(4,757)	(5,797)	(4,832)
Change in AOCL/I before reclassifications to income	0	0	0	0
Reclassifications from AOCL/I to income during the period	52	37	149	112
Other comprehensive (loss) income, net of tax	52	37	149	112
Ending balance	(5,648)	(4,720)	(5,648)	(4,720)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(37,082)	(31,088)	(42,477)	(36,491)
Change in AOCL/I before reclassifications to income	46,319	(3,032)	51,714	2,371
Reclassifications from AOCL/I to income during the period	0	0	0	0
Other comprehensive (loss) income, net of tax	46,319	(3,032)	51,714	2,371
Ending balance	9,237	(34,120)	9,237	(34,120)
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(48,889)	(48,003)	(49,683)	(44,402)
Change in AOCL/I before reclassifications to income	46,328	(956)	44,802	(7,005)
Reclassifications from AOCL/I to income during the period	1,345	1,175	3,665	3,623
Other comprehensive (loss) income, net of tax	47,673	219	48,467	(3,382)
Ending balance	$ (1,216)	$ (47,784)	$ (1,216)	$ (47,784)