Consolidated statements of comprehensive income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 40,591	$ 47,856	$ 32,462
Other comprehensive income, net of tax:
Net change in unrealized gain (loss) in available-for-sale securities, net of taxes of $5,309, $(71), and $802	778	(1,057)	11,549
Reclassification adjustment for gain on sale of securities included in net income, net of tax expense of $298, $91 and $130	(4,109)	(1,753)	(1,870)
Comprehensive income	$ 37,260	$ 45,046	$ 42,141