Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 15,661	$ 64,028	$ 39,511	$ 114,843
Other comprehensive income (loss):
Foreign currency translation gain (loss)	1,048	(70)	1,600	2,855
Comprehensive income	$ 16,709	$ 63,958	$ 41,111	$ 117,698