Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 193,529	$ 130,241	$ 89,388
Foreign currency translation adjustment	(435)	292	(31)
Other comprehensive income (loss), before tax	(435)	292	(31)
Income tax expense on other comprehensive income (loss)	0	0	0
Other comprehensive income (loss), net of tax	(435)	292	(31)
Comprehensive income	$ 193,094	$ 130,533	$ 89,357