Consolidated statements of comprehensive income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 80,236	$ 52,398	$ 40,591
Other comprehensive income (loss), net of tax:
Net change in unrealized (loss) gain in available-for-sale securities, net of taxes of $2,025, $493 and $144	(5,439)	1,162	778
Reclassification adjustment for loss (gain) on sale of securities included in net income, net of taxes of $9, $112 and $298	44	(173)	(4,109)
Net change in unrealized gain in hedging activities, net of taxes of $366, $442, and $0	1,039	685	0
Reclassification adjustment for gain on hedging activities, net of taxes of $45, $0, and $0.	(128)	0	0
Total other comprehensive (loss) income, net of tax	(4,484)	1,674	(3,331)
Comprehensive income	$ 75,752	$ 54,072	$ 37,260