Loans and Leases and the Allowance for Credit Losses - Schedule of Activity in Allowance by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Allowance for Credit Losses:
Balance at Beginning of Period	$ 198,343	$ 138,150	$ 216,252	$ 110,027
Loans and Leases Charged-Off	(4,309)	(8,283)	(10,600)	(15,460)
Recoveries on Loans and Leases Previously Charged-Off	3,125	3,172	6,500	6,609
Net Loans and Leases Recovered (Charged-Off)	(1,184)	(5,111)	(4,100)	(8,851)
Provision for Credit Losses	(16,774)	40,400	(31,767)	74,000
Balance at End of Period	180,385	173,439	180,385	173,439
CECL Adoption Impact | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period				(1,737)
January 1, 2020 | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period				108,290
Commercial
Allowance for Credit Losses:
Balance at Beginning of Period	82,811	67,987	84,847	73,801
Loans and Leases Charged-Off	(456)	(656)	(704)	(1,349)
Recoveries on Loans and Leases Previously Charged-Off	144	1,524	256	1,853
Net Loans and Leases Recovered (Charged-Off)	(312)	868	(448)	504
Provision for Credit Losses	(3,860)	3,667	(5,760)	17,006
Balance at End of Period	78,639	72,522	78,639	72,522
Commercial | CECL Adoption Impact | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period				(18,789)
Commercial | January 1, 2020 | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period				55,012
Consumer
Allowance for Credit Losses:
Balance at Beginning of Period	115,532	70,163	131,405	36,226
Loans and Leases Charged-Off	(3,853)	(7,627)	(9,896)	(14,111)
Recoveries on Loans and Leases Previously Charged-Off	2,981	1,648	6,244	4,756
Net Loans and Leases Recovered (Charged-Off)	(872)	(5,979)	(3,652)	(9,355)
Provision for Credit Losses	(12,914)	36,733	(26,007)	56,994
Balance at End of Period	$ 101,746	$ 100,917	$ 101,746	100,917
Consumer | CECL Adoption Impact | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period				17,052
Consumer | January 1, 2020 | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period				$ 53,278