Summary of Significant Accounting Policies - The Balances in the Company's Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 93,033
Net current-period other comprehensive income	901	$ 4,915
Ending balance	93,644
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(32,342)	(37,447)
Other comprehensive income before reclassifications	901	4,915
Net current-period other comprehensive income	901	4,915
Ending balance	(31,441)	(32,532)
Defined Benefit Pension Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,832)	(1,663)
Other comprehensive income before reclassifications	0	0
Net current-period other comprehensive income	0	0
Ending balance	(1,832)	(1,663)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(34,174)	(39,110)
Other comprehensive income before reclassifications	901	4,915
Net current-period other comprehensive income	901	4,915
Ending balance	$ (33,273)	$ (34,195)