Allowance for Credit Losses (Allowance for Credit Losses Methodology) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Allowance for credit losses on loans and leases
Balance, beginning of period	$ 157,629	$ 144,871
Provision for credit losses for loans and leases	191,875	72,515
Charge-offs	(84,496)	(75,705)
Recoveries	13,394	15,948
Net recoveries (charge-offs)	(71,102)	(59,757)
Balance, end of period	328,401	157,629
Reserve for unfunded commitments
Balance, beginning of period	5,106	4,523
Provision (recapture) for credit losses on unfunded commitments (1)	11,942	583
Balance, end of period	20,286	5,106
Total allowance for credit losses	348,687	162,735
Provision Related to Accrued Interest on Loans Deferred Due to COVID-19	1,000
Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses on loans and leases
Balance, beginning of period	207,628
Balance, end of period		207,628
Reserve for unfunded commitments
Balance, beginning of period	8,344
Balance, end of period		8,344
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses on loans and leases
Balance, beginning of period	49,999
Balance, end of period		49,999
Reserve for unfunded commitments
Impact of adoption CECL		3,238
Commercial Real Estate
Allowance for credit losses on loans and leases
Balance, beginning of period	50,847	47,904
Provision for credit losses for loans and leases	86,186	7,907
Charge-offs	(1,413)	(5,849)
Recoveries	1,013	885
Net recoveries (charge-offs)	(400)	(4,964)
Balance, end of period	141,710	50,847
Reserve for unfunded commitments
Balance, beginning of period	534	628
Provision (recapture) for credit losses on unfunded commitments (1)	10,796	(94)
Balance, end of period	15,360	534
Total allowance for credit losses	157,070	51,381
Commercial Real Estate | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses on loans and leases
Balance, beginning of period	55,924
Balance, end of period		55,924
Reserve for unfunded commitments
Balance, beginning of period	4,564
Balance, end of period		4,564
Commercial Real Estate | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses on loans and leases
Balance, beginning of period	5,077
Balance, end of period		5,077
Reserve for unfunded commitments
Impact of adoption CECL		4,030
Commercial
Allowance for credit losses on loans and leases
Balance, beginning of period	73,820	63,957
Provision for credit losses for loans and leases	101,478	59,651
Charge-offs	(76,488)	(62,098)
Recoveries	8,045	12,310
Net recoveries (charge-offs)	(68,443)	(49,788)
Balance, end of period	150,864	73,820
Reserve for unfunded commitments
Balance, beginning of period	2,539	2,250
Provision (recapture) for credit losses on unfunded commitments (1)	138	289
Balance, end of period	2,190	2,539
Total allowance for credit losses	153,054	76,359
Commercial | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses on loans and leases
Balance, beginning of period	117,829
Balance, end of period		117,829
Reserve for unfunded commitments
Balance, beginning of period	2,052
Balance, end of period		2,052
Commercial | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses on loans and leases
Balance, beginning of period	44,009
Balance, end of period		44,009
Reserve for unfunded commitments
Impact of adoption CECL		(487)
Residential
Allowance for credit losses on loans and leases
Balance, beginning of period	24,714	22,034
Provision for credit losses for loans and leases	(190)	3,066
Charge-offs	(521)	(862)
Recoveries	1,862	476
Net recoveries (charge-offs)	1,341	(386)
Balance, end of period	27,964	24,714
Reserve for unfunded commitments
Balance, beginning of period	149	160
Provision (recapture) for credit losses on unfunded commitments (1)	245	(11)
Balance, end of period	1,661	149
Total allowance for credit losses	29,625	24,863
Residential | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses on loans and leases
Balance, beginning of period	26,813
Balance, end of period		26,813
Reserve for unfunded commitments
Balance, beginning of period	1,416
Balance, end of period		1,416
Residential | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses on loans and leases
Balance, beginning of period	2,099
Balance, end of period		2,099
Reserve for unfunded commitments
Impact of adoption CECL		1,267
Consumer & Other, Net
Allowance for credit losses on loans and leases
Balance, beginning of period	8,248	10,976
Provision for credit losses for loans and leases	4,401	1,891
Charge-offs	(6,074)	(6,896)
Recoveries	2,474	2,277
Net recoveries (charge-offs)	(3,600)	(4,619)
Balance, end of period	7,863	8,248
Reserve for unfunded commitments
Balance, beginning of period	1,884	1,485
Provision (recapture) for credit losses on unfunded commitments (1)	763	399
Balance, end of period	1,075	1,884
Total allowance for credit losses	8,938	10,132
Consumer & Other, Net | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for credit losses on loans and leases
Balance, beginning of period	7,062
Balance, end of period		7,062
Reserve for unfunded commitments
Balance, beginning of period	312
Balance, end of period		312
Consumer & Other, Net | Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
Allowance for credit losses on loans and leases
Balance, beginning of period	$ (1,186)
Balance, end of period		(1,186)
Reserve for unfunded commitments
Impact of adoption CECL		$ (1,572)