CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 7,484	$ 2,552
Short term investments:
Unrealized (loss) gain, net of income tax (benefit) expense of ($2) and $23, respectively	(3)	43
Comprehensive income	$ 7,481	$ 2,595