Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 24,971	$ 24,071	$ 65,124	$ 45,200
Other comprehensive income:
Unrealized gain (loss) on debt securities (net of tax expense of $55 and $489 in 2019, and net of tax benefit of $46 and $207 in 2018, respectively)	164	(179)	1,723	(772)
Accretion of unrealized loss (gain) on debt securities reclassified to held-to-maturity (net of tax expense of $86 and $257 in 2019 and net of tax expense of $336 and $854 in 2018, respectively)	124	(110)	372	1,836
Reclassification adjustment for gains included in net income (net of tax expense of $53 in 2018)	0	0	0	195
Total other comprehensive income	288	(289)	2,095	1,259
Total comprehensive income	$ 25,259	$ 23,782	$ 67,219	$ 46,459