Unaudited Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 21,482	$ 27,066	$ 95,439	$ 79,750
Foreign currency translation adjustment	6	0	72	0
Other comprehensive income (loss), before tax	6	0	72	0
Income tax expense on other comprehensive income (loss)	0	0	0	0
Other comprehensive income (loss), net of tax	6	0	72	0
Comprehensive income	$ 21,488	$ 27,066	$ 95,511	$ 79,750