Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 132,884	$ 129,671	$ 74,345
Other comprehensive income (loss):
Net foreign currency translation adjustment	4,237	(1,798)	0
Total comprehensive income	$ 137,121	$ 127,873	$ 74,345