Accumulated Other Comprehensive Income - Pre-tax and After-tax Changes in the Components of Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax [Abstract]
Change in unrealized gain on available-for-sale debt securities, before tax	$ 14,587	$ 17,054	$ 28,616	$ 32,329
Change in unrealized gain on available-for-sale debt securities, tax	3,603	4,212	7,068	7,985
Change in unrealized gain on available-for-sale debt securities, after tax	10,984	12,842	21,548	24,344
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax [Abstract]
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, before tax			(4)	292
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, tax			(1)	72
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, after tax	0	0	3	(220)
Other Comprehensive Loss, Held-to-maturity Security, OTTI, after Tax and Adjustments [Abstract]
Reclassification of (gain) loss on held-to-maturity securities, before tax	(437)	4	(644)	7
Reclassification of (gain) loss on held-to-maturity securities, tax	(108)	1	(159)	2
Reclassification of (gain) loss on held-to-maturity securities, after tax	(329)	3	(485)	5
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent [Abstract]
Change in unrealized loss on cash flow hedges arising during the period, before tax	(1,563)	(1,679)	(8,442)	(2,944)
Change in unrealized loss on cash flow hedges arising during the period, tax	(386)	(414)	(2,085)	(727)
Change in unrealized loss on cash flow hedges arising during the period, after tax	(1,177)	(1,265)	(6,357)	(2,217)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Reclassification of loss on cash flow hedges, before tax	311	5	474	5
Reclassification of loss on cash flow hedges, tax	77	1	117	1
Reclassification of loss on cash flow hedges, after tax	(234)	(4)	(357)	(4)
OCI, Net of Tax [Abstract]
Total other comprehensive income, before tax	12,898	15,384	20,000	29,689
Total other comprehensive income, tax	3,186	3,800	4,940	7,333
Total other comprehensive income, after-tax	$ 9,712	$ 11,584	$ 15,060	$ 22,356