Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	$ (58,130)	$ (24,157)	$ (54,595)	$ (21,181)
Other comprehensive income before reclassifications	[1]	3,056	(2,781)	(394)	(5,672)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	(85)	(85)	(170)	(170)
Other comprehensive income (loss)	[1]	2,971	(2,866)	(564)	(5,842)
Ending balance	[1]	(55,159)	(27,023)	(55,159)	(27,023)
Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(306)	(568)	(364)	(637)
Other comprehensive income before reclassifications	[1]	64	62	122	131
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	0	0
Other comprehensive income (loss)	[1]	64	62	122	131
Ending balance	[1]	(242)	(506)	(242)	(506)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(8,692)	0	(4,709)	0
Other comprehensive income before reclassifications	[1]	779	0	(3,204)	0
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	0	0
Other comprehensive income (loss)	[1]	779	0	(3,204)	0
Ending balance	[1]	(7,913)	0	(7,913)	0
Investment in Debt Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	126	4,629	126	7,861
Other comprehensive income before reclassifications	[1]	0	(2,230)	0	(5,462)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	0	0
Other comprehensive income (loss)	[1]	0	(2,230)	0	(5,462)
Ending balance	[1]	126	2,399	126	2,399
Defined Benefit Plan Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(49,258)	(28,218)	(49,648)	(28,405)
Other comprehensive income before reclassifications	[1]	2,213	(613)	2,688	(341)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	(85)	(85)	(170)	(170)
Other comprehensive income (loss)	[1]	2,128	(698)	2,518	(511)
Ending balance	[1]	$ (47,130)	$ (28,916)	$ (47,130)	$ (28,916)

[1] All amounts are net of tax. Amounts in parentheses indicate debits