Accumulated Other Comprehensive Income (Loss) - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Reclassification Adjustments out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains on sales of available for sale securities	$ 1,761	$ 3,068	$ 3,560	$ 7,680
Interest expense - subordinated debentures and term loans	1,659	1,639	3,316	3,584
Income tax expense	(10,294)	(4,623)	(19,246)	(8,113)
Total reclassifications for the period, net of tax	55,559	32,992	105,028	67,255
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	1,186	2,242	2,407	5,785
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	1,761	3,068	3,560	7,680
Income tax expense	(370)	(644)	(748)	(1,613)
Total reclassifications for the period, net of tax	1,391	2,424	2,812	6,067
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	55	49	108	75
Total reclassifications for the period, net of tax	(205)	(182)	(405)	(282)
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	$ (260)	$ (231)	$ (513)	$ (357)