Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2016	Jun. 30, 2016
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance			$ 845,127
Other comprehensive income before reclassifications		$ (17,892)	(2,727)
Amounts reclassified from OCI		(3,050)	(2,636)
Ending balance		862,318	862,318
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance		(154,483)	(170,062)
Ending balance		(175,425)	(175,425)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance	[1]	(1,028)	164
Other comprehensive income before reclassifications	[1]	828	(743)
Amounts reclassified from OCI	[1]	170	549
Ending balance	[1]	(30)	(30)
Pension Items [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance	[1]	(4,357)	(4,393)
Other comprehensive income before reclassifications	[1]	0	0
Amounts reclassified from OCI	[1]	37	73
Ending balance	[1]	(4,320)	(4,320)
Foreign Currency Items [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance		(149,098)	(165,833)
Other comprehensive income before reclassifications		(18,720)	(1,985)
Amounts reclassified from OCI		(3,257)	(3,257)
Ending balance		$ (171,075)	$ (171,075)

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