Loans and Allowance for Credit Losses Summary Of Gross Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 17,102,868	$ 16,864,336
Unearned income	(25,465)	(26,810)
Net loans	17,077,403	16,837,526	$ 16,262,633
Real-estate - commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	6,895,069	6,700,776
Net loans	6,895,069	6,700,776	6,428,688
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	4,451,239	4,446,701
Net loans	4,451,239	4,446,701	4,429,538
Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,718,290	2,641,465
Net loans	2,718,290	2,641,465	2,313,908
Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,292,677	1,314,944
Net loans	1,292,677	1,314,944	1,413,500
Real estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	947,768	971,079
Net loans	947,768	971,079	953,087
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	468,172	463,164
Net loans	468,172	463,164	$ 433,545
Equipment lease financing and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	327,272	322,625
Overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 2,381	$ 3,582

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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