Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 88,574	$ 71,932	$ 42,470
Other comprehensive income:
Unrealized gain (loss) on debt securities (net of tax expense of $470 in 2019, and net of tax benefit of $33 and $204 in 2018 and 2017, respectively)	1,655	(162)	(295)
Accretion of unrealized loss on debt securities reclassified to held-to-maturity (net of tax expense of $404, $1,186, and $480 in 2019, 2018 and 2017, respectively)	587	1,719	695
Reclassification adjustment for gains included in net income (net of tax expense of $53 in 2018)		195	0
Total other comprehensive income	2,242	1,752	400
Total comprehensive income	$ 90,816	$ 73,684	$ 42,870