Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 13,341	$ 16,644	$ 19,531	$ 41,388
Foreign currency translation (loss) gain	(950)	1,048	(1,796)	1,600
Revaluation of interest rate swap, net of tax of $0.5 million	(1,162)	0	(1,162)	0
Total other comprehensive (loss) gain	(2,112)	1,048	(2,958)	1,600
Comprehensive income	$ 11,229	$ 17,692	16,573	$ 42,988
AOCI tax			$ 500