Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 309,012	$ 300,766	$ 303,373
Ending Balance	318,026	309,012	300,766
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(4,778)	(5,292)	(2,193)
Other comprehensive income/(loss) before reclassifications	1,142	514	(3,099)
Amounts reclassified from AOCI	0	0	0
Net current period other comprehensive income/(loss)	1,142	514	(3,099)
Ending Balance	(3,636)	(4,778)	(5,292)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	1,369	(49)	(867)
Other comprehensive income/(loss) before reclassifications	(127)	1,834	2,718
Amounts reclassified from AOCI	(255)	(416)	(1,900)
Net current period other comprehensive income/(loss)	(382)	1,418	818
Ending Balance	987	1,369	(49)
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,409)	(5,341)	(3,060)
Other comprehensive income/(loss) before reclassifications	1,015	2,348	(381)
Amounts reclassified from AOCI	(255)	(416)	(1,900)
Net current period other comprehensive income/(loss)	760	1,932	(2,281)
Ending Balance	$ (2,649)	$ (3,409)	$ (5,341)