Changes in Accumulated Other Comprehensive Income - Schedule of Changes in AOCI(L) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Defined benefit pension, balance January 1	$ 13,656	$ 12,320
Foreign currency translation, balance January 1	11,702	10,496
Total, balance January 1	(1,954)	(1,824)
Other comprehensive income (loss) before reclassifications, defined benefit plan	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax	6,119	1,206
Total, other comprehensive income (loss) before reclassifications	6,119	1,206
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	555	(1,336)
Total, amounts reclassified from accumulated other comprehensive income (loss)	555	(1,336)
Defined benefit pension, other comprehensive income (loss)	555	(1,336)	$ (3,101)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent	6,119	1,206
Total, other comprehensive income (loss)	6,674	(130)
Defined benefit pension, balance December 31	13,101	13,656	12,320
Foreign currency translation, balance December 31	17,821	11,702	10,496
Total, balance December 31	$ 4,720	$ (1,954)	$ (1,824)