Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 22,516	$ 16,315	$ 65,688	$ 40,661
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) on investment securities arising during the period, net of income tax expense (benefit) for three months of $(1,328) and $(493), and for nine months of $(3,926) and $775, respectively	(4,048)	(805)	(11,968)	1,265
Less: Reclassification adjustment for realized gains on sale of securities available for sale included in net income, net of income tax expense for three months of $0 and $8, and for nine months of $2 and $8, respectively	0	(13)	(7)	(13)
Total other comprehensive income (loss)	(4,048)	(818)	(11,975)	1,252
Total comprehensive income	$ 18,468	$ 15,497	$ 53,713	$ 41,913