Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Consolidated Statements of Comprehensive Income
Net income	$ 17,368	$ 10,251	$ 27,665	$ 15,076
Other comprehensive income:
Unrealized net gain on marketable securities, net of tax	184	381	350	1,037
Other comprehensive income:	184	381	350	1,037
Comprehensive income	$ 17,552	$ 10,632	$ 28,015	$ 16,113