Allowance for Credit Losses and Credit Quality - Rollfowards of the Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	$ 113,052	$ 157,446
Charge-offs	(15,649)	(24,431)
Recoveries	10,172	5,777
Net (charge-offs) recoveries	(5,477)	(18,654)
Provision for credit losses	92,990	10,122
Other	(174)	(942)
Balance, end of period	406,383	147,972
Allowance for loan, leases and unfunded commitments [Roll Forward]
Balance, beginning of period	116,580	158,874
Charge-offs	(15,649)	(24,431)
Recoveries	10,172	5,777
Net (charge-offs) recoveries	(5,477)	(18,654)
Provision for credit losses	96,943	10,635
Other	(174)	(942)
Balance, end of period	428,571	149,913
Unfunded Loan Commitment
Unfunded commitments [Roll Forward]
Balance, beginning of period	3,528	1,428
Charge-offs	0	0
Recoveries	0	0
Net (charge-offs) recoveries	0	0
Provision for credit losses	3,953	513
Other	0	0
Balance, end of period	22,188	1,941
Consumer
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	28,572	80,017
Charge-offs	(5,900)	(16,866)
Recoveries	4,760	4,857
Net (charge-offs) recoveries	(1,140)	(12,009)
Provision for credit losses	40,288	7,258
Other	0	(969)
Balance, end of period	175,057	74,297
Commercial
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	84,480	77,429
Charge-offs	(9,749)	(7,565)
Recoveries	5,412	920
Net (charge-offs) recoveries	(4,337)	(6,645)
Provision for credit losses	52,702	2,864
Other	(174)	27
Balance, end of period	231,326	$ 73,675
Cumulative Effect, Period of Adoption, Adjustment
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	205,992
Allowance for loan, leases and unfunded commitments [Roll Forward]
Balance, beginning of period	220,699
Cumulative Effect, Period of Adoption, Adjustment | Unfunded Loan Commitment
Unfunded commitments [Roll Forward]
Balance, beginning of period	14,707
Cumulative Effect, Period of Adoption, Adjustment | Consumer
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	107,337
Cumulative Effect, Period of Adoption, Adjustment | Commercial
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	98,655
Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	319,044
Allowance for loan, leases and unfunded commitments [Roll Forward]
Balance, beginning of period	337,279
Cumulative Effect, Period of Adoption, Adjusted Balance | Unfunded Loan Commitment
Unfunded commitments [Roll Forward]
Balance, beginning of period	18,235
Cumulative Effect, Period of Adoption, Adjusted Balance | Consumer
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	135,909
Cumulative Effect, Period of Adoption, Adjusted Balance | Commercial
Allowance for loan and lease losses [Roll Forward]
Balance, beginning of period	$ 183,135