Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Changes in accumulated other comprehensive income [Roll Forward]
Balance			$ 391,979
Other comprehensive income before reclassifications	$ (1,758)		31
Amounts reclassified from accumulated other comprehensive income	58		212
Total other comprehensive income (loss), net of tax	(1,700)	$ 1,384	243	$ (1,334)
Balance	420,482		420,482
AOCI Attributable to Parent [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance	(4,531)		(6,474)
Total other comprehensive income (loss), net of tax			243
Balance	(6,231)		(6,231)
Foreign Currency Translation Adjustments [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance	(4,173)		(5,958)
Other comprehensive income before reclassifications	(1,938)		(153)
Amounts reclassified from accumulated other comprehensive income	0		0
Total other comprehensive income (loss), net of tax	(1,938)		(153)
Balance	(6,111)		(6,111)
Unrecognized Postretirement Benefit Costs (Credit) [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance	(358)		(516)
Other comprehensive income before reclassifications	180		184
Amounts reclassified from accumulated other comprehensive income	58		212
Total other comprehensive income (loss), net of tax	238		396
Balance	$ (120)		$ (120)