Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	$ (18,327)	$ (58,130)	$ (20,939)	$ (54,595)
Other comprehensive income (loss) before reclassifications	[1]	1,289	3,056	4,083	(394)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	(56)	(85)	(238)	(170)
Other comprehensive income (loss)	[1]	1,233	2,971	3,845	(564)
Ending balance	[1]	(17,094)	(55,159)	(17,094)	(55,159)
Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(51)	(306)	(111)	(364)
Other comprehensive income (loss) before reclassifications	[1]	60	64	120	122
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	0	0
Other comprehensive income (loss)	[1]	60	64	120	122
Ending balance	[1]	9	(242)	9	(242)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(9,536)	(8,692)	(12,041)	(4,709)
Other comprehensive income (loss) before reclassifications	[1]	52	779	2,557	(3,204)
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	0	0
Other comprehensive income (loss)	[1]	52	779	2,557	(3,204)
Ending balance	[1]	(9,484)	(7,913)	(9,484)	(7,913)
Investment in Debt Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	0	126	126	126
Other comprehensive income (loss) before reclassifications	[1]	0	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	0	(126)	0
Other comprehensive income (loss)	[1]	0	0	(126)	0
Ending balance	[1]	0	126	0	126
Defined Benefit Plan Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(8,740)	(49,258)	(8,913)	(49,648)
Other comprehensive income (loss) before reclassifications	[1]	1,177	2,213	1,406	2,688
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	(56)	(85)	(112)	(170)
Other comprehensive income (loss)	[1]	1,121	2,128	1,294	2,518
Ending balance	[1]	$ (7,619)	$ (47,130)	$ (7,619)	$ (47,130)

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