Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 18,980	$ 15,702	$ 40,153	$ 21,129
Other comprehensive income:
Unrealized gain (loss) on debt securities (net of tax expense of $260 and $434 in 2019, and net of tax benefit of $74 and $159 in 2018, respectively)	915	(272)	1,559	(593)
Accretion of unrealized loss on debt securities reclassified to held-to-maturity (net of tax expense of $85 and $171 in 2019 and net of tax expense of $460 and $518 in 2018, respectively)	123	1,730	248	1,946
Reclassification adjustment for gains included in net income (net of tax expense of $52 and $53 in 2018, respectively)	0	194	0	195
Total other comprehensive income	1,038	1,652	1,807	1,548
Total comprehensive income	$ 20,018	$ 17,354	$ 41,960	$ 22,677