Loans and Allowance for Loan Losses (Schedule of Allowances for Loan Losses and Recorded Investment in Loans) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 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	$ 493,452	$ 257,036	$ 281,402	$ 250,555
Charge-offs		(30,778)	(16,865)	(54,652)	(37,563)
Recoveries		6,732	5,086	10,545	8,696
Provision for (reversal of) loan losses		119,242	12,119	268,359	35,688
Ending balance	281,402	588,648	257,376	588,648	257,376
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		216,950	135,639		133,123
Charge-offs		(23,245)	(11,095)	(38,130)	(24,133)
Recoveries		3,261	1,821	5,002	3,810
Provision for (reversal of) loan losses		32,949	11,639	119,571	25,204
Ending balance	145,782	229,915	138,004	229,915	138,004
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		107,117	69,009		68,796
Charge-offs		(689)	(861)	(1,706)	(2,093)
Recoveries		536	1,954	935	2,298
Provision for (reversal of) loan losses		64,562	(6,639)	105,518	(5,538)
Ending balance	67,430	171,526	63,463	171,526	63,463
Commercial Real Estate | Impact from Adoption
Allowance for loan losses:
Beginning balance	(651)			(651)
Ending balance	(651)
Consumer
Allowance for loan losses:
Beginning balance		169,385	52,388		48,636
Charge-offs		(6,844)	(4,909)	(14,816)	(11,337)
Recoveries		2,935	1,311	4,608	2,588
Provision for (reversal of) loan losses		21,731	7,119	43,270	16,022
Ending balance	68,190	$ 187,207	$ 55,909	187,207	$ 55,909
Consumer | Impact from Adoption
Allowance for loan losses:
Beginning balance	85,955			$ 85,955
Ending balance	$ 85,955