Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 10,233	$ 10,973	$ 10,752	$ 14,047
Unrealized gains on investments, net of tax	4	6	58	33
Comprehensive income	$ 10,237	$ 10,979	$ 10,810	$ 14,080