Accumulated Other Comprehensive Income - Pre-tax and After-tax Changes in the Components of Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 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	$ 125	$ 9,320	$ 28,741	$ 41,649
Change in unrealized gain on available-for-sale debt securities, tax	31	2,302	7,099	10,287
Change in unrealized gain on available-for-sale debt securities, after tax	94	7,018	21,642	31,362
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	(417)	(337)	(421)	(45)
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, tax	(103)	(83)	(104)	(11)
Reclassification adjustment for realized (gain) loss on sale of available-for-sale debt securities, after tax	314	254	317	34
Other Comprehensive Loss, Held-to-maturity Security, OTTI, after Tax and Adjustments [Abstract]
Reclassification of (gain) loss on held-to-maturity securities, before tax	(936)	13	(1,580)	20
Reclassification of (gain) loss on held-to-maturity securities, tax	(231)	3	(390)	5
Reclassification of (gain) loss on held-to-maturity securities, after tax	(705)	10	(1,190)	15
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	146	(888)	(8,296)	(3,833)
Change in unrealized loss on cash flow hedges arising during the period, tax	36	(219)	(2,049)	(947)
Change in unrealized loss on cash flow hedges arising during the period, after tax	110	(669)	(6,247)	(2,886)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Reclassification of loss on cash flow hedges, before tax	683	42	1,157	47
Reclassification of loss on cash flow hedges, tax	169	10	286	11
Reclassification of loss on cash flow hedges, after tax	(514)	(32)	(871)	(36)
OCI, Net of Tax [Abstract]
Total other comprehensive income, before tax	(399)	8,150	19,601	37,838
Total other comprehensive income, tax	(98)	2,013	4,842	9,345
Total other comprehensive income (loss), after-tax	$ (301)	$ 6,137	$ 14,759	$ 28,493