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	$ 71,932	$ 42,470	$ 23,046
Other comprehensive income:
Unrealized loss on debt securities (net of tax benefit of $33, $204, and $221 in 2018, 2017, and 2016, respectively)	(162)	(295)	(321)
Accretion of unrealized loss on securities reclassified to held-to-maturity (net of tax expense of $1,186, $480, and $556 in 2018, 2017 and 2016, respectively)	1,719	695	806
Reclassification adjustment for gains included in net income (net of tax expense of $53 and $5 in 2018 and 2016, respectively)	195	0	7
Total other comprehensive income	1,752	400	492
Total comprehensive income	$ 73,684	$ 42,870	$ 23,538