Accumulated Other Comprehensive Income (Loss) - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains on sales of available for sale securities	$ 1,756	$ 1,817	$ 5,316	$ 9,497
Interest expense - subordinated debentures and term loans	1,660	1,691	4,976	5,275
Income tax expense	(9,062)	(5,621)	(28,308)	(13,734)
Total reclassifications for the period, net of tax	52,770	36,210	157,798	103,465
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period, net of tax	1,177	1,203	3,585	6,989
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on available for sale securities
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains on sales of available for sale securities	1,756	1,817	5,316	9,497
Income tax expense	(369)	(382)	(1,116)	(1,994)
Total reclassifications for the period, net of tax	1,387	1,435	4,200	7,503
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on cash flow hedges
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	56	62	164	137
Total reclassifications for the period, net of tax	(210)	(232)	(615)	(514)
Amount Reclassified from Accumulated Other Comprehensive Income (Loss) for the Period | Unrealized gains (losses) on cash flow hedges | Interest rate contracts
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Interest expense - subordinated debentures and term loans	$ (266)	$ (294)	$ (779)	$ (651)