Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
		Sep. 30, 2016	Sep. 30, 2016
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance			$ 845,127
Other comprehensive income before reclassifications		$ (3,013)	(5,741)
Amounts reclassified from OCI		178	(2,457)
Ending balance		878,396	878,396
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance		(175,425)	(170,062)
Ending balance		(178,260)	(178,260)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance	[1]	(30)	164
Other comprehensive income before reclassifications	[1]	(322)	(1,065)
Amounts reclassified from OCI	[1]	142	691
Ending balance	[1]	(210)	(210)
Pension Items [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance	[1]	(4,320)	(4,393)
Other comprehensive income before reclassifications	[1]	0	0
Amounts reclassified from OCI	[1]	36	109
Ending balance	[1]	(4,284)	(4,284)
Foreign Currency Items [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Beginning balance		(171,075)	(165,833)
Other comprehensive income before reclassifications		(2,691)	(4,676)
Amounts reclassified from OCI		0	(3,257)
Ending balance		$ (173,766)	$ (173,766)

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