Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		$ 925,646	$ 842,658	$ 934,336	$ 881,589
Other comprehensive income (loss) before reclassifications		8,551	10,104	(6,352)	(34,686)
Amounts reclassified from OCI		9,758	(7,467)	9,522	(7,030)
Ending balance		944,277	860,716	944,277	860,716
Accumulated Other Comprehensive (Loss) Income [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(174,230)	(207,361)	(159,091)	(163,008)
Ending balance		(155,921)	(204,724)	(155,921)	(204,724)
Cash Flow Hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]	1,180	(1,635)	749	(199)
Other comprehensive income (loss) before reclassifications	[1]	124	(19)	844	(1,884)
Amounts reclassified from OCI	[1]	(487)	742	(776)	1,171
Ending balance	[1]	817	(912)	817	(912)
Pension Items [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]	(1,913)	(664)	(1,965)	(672)
Other comprehensive income (loss) before reclassifications	[1]	0	0	0	0
Amounts reclassified from OCI	[1]	52	8	104	16
Ending balance	[1]	(1,861)	(656)	(1,861)	(656)
Foreign Currency Items [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(173,497)	(205,062)	(157,875)	(162,137)
Other comprehensive income (loss) before reclassifications		8,427	10,123	(7,196)	(32,802)
Amounts reclassified from OCI		10,193	(8,217)	10,194	(8,217)
Ending balance		$ (154,877)	$ (203,156)	$ (154,877)	$ (203,156)

[1] Cash Flow Hedges and Pension Items are net of tax.