Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Consolidated Statements of Comprehensive Income (unaudited) [Abstract]
Net income	$ 10,730	$ 8,817	$ 20,111	$ 17,978
Securities available for sale
Unrealized gains (losses) arising during period	3,920	(1,198)	9,284	(5,063)
Change in unrealized losses for which a portion of other than temporary impairment has been recognized in earnings	0	(2)	(2)	(3)
Reclassification adjustments for (gains) losses included in earnings	0	26	(137)	45
Unrealized gains (losses) recognized in other comprehensive income (loss) on securities available for sale	3,920	(1,174)	9,145	(5,021)
Income tax expense (benefit)	823	(246)	1,920	(1,054)
Unrealized gains (losses) recognized in other comprehensive income (loss) on securities available for sale, net of tax	3,097	(928)	7,225	(3,967)
Derivative instruments
Unrealized gain (loss) arising during period	(756)	327	(1,668)	1,011
Reclassification adjustment for income recognized in earnings	(142)	(53)	(291)	(59)
Unrealized gains (losses) recognized in other comprehensive income (loss) on derivative instruments	(898)	274	(1,959)	952
Income tax expense (benefit)	(187)	58	(411)	200
Unrealized gains (losses) recognized in other comprehensive income (loss) on derivative instruments, net of tax	(711)	216	(1,548)	752
Other comprehensive income (loss)	2,386	(712)	5,677	(3,215)
Comprehensive income	$ 13,116	$ 8,105	$ 25,788	$ 14,763