Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 63,309	$ 88,574	$ 71,932
Other comprehensive income:
Unrealized gain (loss) on debt securities (net of tax expense of $411 and $470 in 2020 and 2019, respectively, and net of tax benefit of $33 in 2018)	1,039	1,655	(162)
Accretion of unrealized loss on debt securities reclassified to held-to-maturity (net of tax expense of $310, $404 and $1,186 in 2020, 2019, and 2018, respectively)	446	587	1,719
Reclassification adjustment for gains included in net income (net of tax expense of $101 and $53 in 2020 and 2018, respectively)	344	0	195
Total other comprehensive income	1,829	2,242	1,752
Total comprehensive income	65,138	90,816	73,684
Less: Dividends on preferred shares	2,097	0	0
Total comprehensive income available to common stockholders	$ 63,041	$ 90,816	$ 73,684