Changes in Accumulated Other Comprehensive Income (Loss) - Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 353,396	$ 273,456	$ 245,225
Other comprehensive income (loss)	(23,331)	27,085	(13,934)
Amounts reclassified from accumulated other comprehensive loss	794	717	569
Ending balance	369,275	353,396	273,456
Total Accumulated Other Comprehensive (Loss) Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(20,148)	(47,950)	(34,585)
Ending balance	(42,685)	(20,148)	(47,950)
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,221)	(27,885)	(16,920)
Other comprehensive income (loss)		25,664	(10,965)
Amounts reclassified from accumulated other comprehensive loss	0
Ending balance	(18,458)	(2,221)	(27,885)
Defined Benefit Pension Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18,049)	(20,065)	(17,665)
Other comprehensive income (loss)	(4,998)	1,299	(2,969)
Amounts reclassified from accumulated other comprehensive loss	794	717	569
Ending balance	(22,253)	(18,049)	(20,065)
Gains and Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	122	0	0
Other comprehensive income (loss)		122	0
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Ending balance	$ (1,974)	$ 122	$ 0