Loans and Allowance for Loan Losses (Schedule of Allowances for Loan Losses and Recorded Investment in Loans) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member			us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201602Member
Allowance for loan losses:
Beginning balance	$ 281,402	$ 588,648	$ 257,376	$ 281,402	$ 250,555
Charge-offs		(35,346)	(24,726)	(89,999)	(62,290)
Recoveries		6,880	4,801	17,426	13,498
Provision for loan losses		43,618	27,562	311,977	63,250
Ending balance	281,402	603,800	265,013	603,800	265,013
Impact from Adoption
Allowance for loan losses:
Beginning balance	82,994			82,994
Ending balance	82,994
Commercial & Industrial
Allowance for loan losses:
Beginning balance		229,915	138,004		133,123
Charge-offs		(19,367)	(15,425)	(57,497)	(39,558)
Recoveries		3,796	2,276	8,798	6,087
Provision for loan losses		46,256	17,156	165,827	42,359
Ending balance	145,782	260,600	142,011	260,600	142,011
Commercial & Industrial | Impact from Adoption
Allowance for loan losses:
Beginning balance	(2,310)			(2,310)
Ending balance	(2,310)
Commercial Real Estate
Allowance for loan losses:
Beginning balance		171,526	63,463		68,796
Charge-offs		(6,878)	(3,275)	(8,585)	(5,369)
Recoveries		1,225	1,490	2,160	3,788
Provision for loan losses		(22,068)	280	83,451	(5,257)
Ending balance	67,430	143,805	61,958	143,805	61,958
Commercial Real Estate | Impact from Adoption
Allowance for loan losses:
Beginning balance	(651)			(651)
Ending balance	(651)
Consumer
Allowance for loan losses:
Beginning balance		187,207	55,909		48,636
Charge-offs		(9,101)	(6,026)	(23,917)	(17,363)
Recoveries		1,859	1,035	6,468	3,623
Provision for loan losses		19,430	10,126	62,699	26,148
Ending balance	68,190	$ 199,395	$ 61,044	199,395	$ 61,044
Consumer | Impact from Adoption
Allowance for loan losses:
Beginning balance	85,955			$ 85,955
Ending balance	$ 85,955