Loans and Leases and the Allowance for Credit Losses - Schedule of Activity in Allowance by Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Credit Losses:
Balance at Beginning of Period	$ 110,027	$ 106,693	$ 107,346
Loans and Leases Charged-Off	(21,038)	(23,955)	(24,564)
Recoveries on Loans and Leases Previously Charged-Off	13,900	11,289	10,486
Net Loans and Leases Recovered (Charged-Off)	(7,138)	(12,666)	(14,078)
Provision for Credit Losses	115,100	16,000	13,425
Balance at End of Period	216,252	110,027	106,693
Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	110,027
Balance at End of Period		110,027
CECL Adoption Impact | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	(1,737)
Balance at End of Period		(1,737)
January 1, 2020 | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	108,290
Balance at End of Period		108,290
Commercial
Allowance for Credit Losses:
Balance at Beginning of Period	73,801	66,874	65,822
Loans and Leases Charged-Off	(1,697)	(2,738)	(1,505)
Recoveries on Loans and Leases Previously Charged-Off	2,328	1,513	2,039
Net Loans and Leases Recovered (Charged-Off)	631	(1,225)	534
Provision for Credit Losses	29,204	8,152	518
Balance at End of Period	84,847	73,801	66,874
Commercial | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	73,801
Balance at End of Period		73,801
Commercial | CECL Adoption Impact | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	(18,789)
Balance at End of Period		(18,789)
Commercial | January 1, 2020 | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	55,012
Balance at End of Period		55,012
Consumer
Allowance for Credit Losses:
Balance at Beginning of Period	36,226	39,819	41,524
Loans and Leases Charged-Off	(19,341)	(21,217)	(23,059)
Recoveries on Loans and Leases Previously Charged-Off	11,572	9,776	8,447
Net Loans and Leases Recovered (Charged-Off)	(7,769)	(11,441)	(14,612)
Provision for Credit Losses	85,896	7,848	12,907
Balance at End of Period	131,405	36,226	$ 39,819
Consumer | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	36,226
Balance at End of Period		36,226
Consumer | CECL Adoption Impact | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	17,052
Balance at End of Period		17,052
Consumer | January 1, 2020 | Accounting Standards Update 2016-13
Allowance for Credit Losses:
Balance at Beginning of Period	$ 53,278
Balance at End of Period		$ 53,278