Loans and Leases and the Allowance for Credit Losses - Schedule of Activity in Allowance by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Allowance for Credit Losses:
Balance at Beginning of Period	$ 216,252	$ 110,027
Loans and Leases Charged-Off	(6,291)	(7,177)
Recoveries on Loans and Leases Previously Charged-Off	3,375	3,437
Net Loans and Leases Recovered (Charged-Off)	(2,916)	(3,740)
Provision for Credit Losses	(14,993)	33,600
Balance at End of Period	198,343	138,150
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	84,847	73,801
Loans and Leases Charged-Off	(248)	(693)
Recoveries on Loans and Leases Previously Charged-Off	112	329
Net Loans and Leases Recovered (Charged-Off)	(136)	(364)
Provision for Credit Losses	(1,900)	13,339
Balance at End of Period	82,811	67,987
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	131,405	36,226
Loans and Leases Charged-Off	(6,043)	(6,484)
Recoveries on Loans and Leases Previously Charged-Off	3,263	3,108
Net Loans and Leases Recovered (Charged-Off)	(2,780)	(3,376)
Provision for Credit Losses	(13,093)	20,261
Balance at End of Period	$ 115,532	70,163
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