Loans and Allowance for Credit Losses Summary Of Gross Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	$ 15,724,738	$ 15,795,918
Deferred Revenue	28,454	27,671
Loans, net of unearned income	15,696,284	15,768,247	$ 14,963,177
Real-estate - commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	6,332,508	6,364,804
Loans, net of unearned income	6,332,508	6,364,804	6,118,533
Commercial - industrial, financial and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	4,299,072	4,300,297
Loans, net of unearned income	4,299,072	4,300,297	4,167,809
Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	1,514,241	1,559,719
Loans, net of unearned income	1,514,241	1,559,719	1,595,901
Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	1,976,524	1,954,711
Loans, net of unearned income	1,976,524	1,954,711	1,665,142
Real-estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	976,131	1,006,935
Loans, net of unearned income	976,131	1,006,935	882,983
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	326,766	313,783
Loans, net of unearned income	326,766	313,783	$ 288,826
Leasing and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	297,465	291,556
Overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross of unearned income	$ 2,031	$ 4,113

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- Definition

Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 13.A.3)
-URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 13.A.4(a).Q1)
-URI http://asc.fasb.org/extlink&oid=65893310&loc=d3e214044-122780

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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.

+ References

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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