SCHEDULE I - Parent Company Information - Condensed Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net income	$ 62,158	$ 14,069	$ 6,460
Other comprehensive income:
Currency translation adjustment	1,061	(868)	(796)
Derivative instruments
Unrealized gains on derivative instruments	896	69
Tax (expense) benefit related to items of other comprehensive income	(686)	275	275
Total comprehensive income	63,429	13,545	5,939
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net income	62,158	14,069	6,460
Other comprehensive income:
Currency translation adjustment	1,061	(868)	(796)
Derivative instruments
Unrealized gains on derivative instruments	896	69
Net gain (loss) recognized in other comprehensive income	1,957	(799)	(796)
Tax (expense) benefit related to items of other comprehensive income	(686)	275	275
Other comprehensive income from (loss)	1,271	(524)	(521)
Total comprehensive income	$ 63,429	$ 13,545	$ 5,939