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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 334,931	$ 211,389	$ 209,096	$ 212,353
Provision charged to expense	40,003	11,900	116,088	20,500
Charge-offs	(18,074)	(14,382)	(28,235)	(27,416)
Recoveries	1,662	2,764	4,005	6,234
Balance, end of period	334,931	211,389	209,096	212,353	$ 358,522	$ 334,931	$ 209,096	$ 211,671	$ 211,389	$ 212,353
ALLL, Individually evaluated for impairment					19,755			14,781
ALLL, Collectively evaluated for impairment					338,767			196,890
Loan and lease balances, Individually evaluated for impairment					323,156			253,247
Loan and lease balances, Collectively evaluated for impairment					21,479,361			19,016,636
Loans and leases					21,802,517		20,036,986	19,269,883
Allowance for credit losses on loans and leases							209,096
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses on loans and leases						0	57,568		0	0
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	261,926	164,057	161,669	164,073
Provision charged to expense	44,605	7,920	115,848	15,910
Charge-offs	(15,294)	(8,130)	(20,868)	(16,940)
Recoveries	283	497	847	1,301
Balance, end of period	261,926	164,057	161,669	164,073	291,520	261,926	161,669	164,344	164,057	164,073
ALLL, Individually evaluated for impairment					15,271			9,520
ALLL, Collectively evaluated for impairment					276,249			154,824
Loan and lease balances, Individually evaluated for impairment					165,010			115,747
Loan and lease balances, Collectively evaluated for impairment					14,589,073			12,134,141
Loans and leases					14,754,083		12,830,177	12,249,888
Commercial Portfolio Segment [Member] \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses on loans and leases						0	34,024		0	0
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	73,005	47,332	47,427	48,280
Provision charged to expense	(4,602)	3,980	240	4,590
Charge-offs	(2,780)	(6,252)	(7,367)	(10,476)
Recoveries	1,379	2,267	3,158	4,933
Balance, end of period	$ 73,005	$ 47,332	$ 47,427	$ 48,280	67,002	73,005	47,427	47,327	47,332	48,280
ALLL, Individually evaluated for impairment					4,484			5,261
ALLL, Collectively evaluated for impairment					62,518			42,066
Loan and lease balances, Individually evaluated for impairment					158,146			137,500
Loan and lease balances, Collectively evaluated for impairment					6,890,288			6,882,495
Loans and leases					$ 7,048,434		7,206,809	$ 7,019,995
Consumer Portfolio Segment [Member] \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses on loans and leases						$ 0	$ 23,544		$ 0	$ 0