Other Comprehensive (Loss) Income - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of securities, net	$ 0	$ (338)	$ 0	$ (347)
Tax expense	(1,373)	574	(1,644)	(2,058)
Interest expense	1,970	1,566	5,411	4,543
Net of tax	(4,898)	1,666	(5,207)	(1,257)
Unrealized gains and losses on securities available-for-sale: | Reclassifications Out of Accumulated Other Comprehensive (Loss) Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of securities, net	0	(338)	0	(347)
Tax expense	0	119	0	121
Net of tax	0	(219)	0	(226)
Gains on derivative instruments: | Interest Rate Contract | Reclassifications Out of Accumulated Other Comprehensive (Loss) Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax expense	14	1	37	1
Interest expense	(74)	(4)	(176)	(4)
Net of tax	$ (60)	$ (3)	$ (139)	$ (3)