Loans and Loans Held for Sale - Composition of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Composition of the loans
Portfolio loans, net of unearned income	$ 5,807,807	$ 5,761,449
Loans held for sale	4,207	4,485
Total Loans	5,812,014	5,765,934
Commercial real estate
Composition of the loans
Portfolio loans, net of unearned income		2,685,994
Total Loans	2,826,372	2,685,994
Commercial and industrial
Composition of the loans
Portfolio loans, net of unearned income		1,433,266
Total Loans	1,451,371	1,433,266
Commercial construction
Composition of the loans
Portfolio loans, net of unearned income		384,334
Total Loans	283,783	384,334
Residential mortgage
Composition of the loans
Total Loans	699,867	698,774
Home equity
Composition of the loans
Total Loans	472,451	487,326
Installment and other consumer
Composition of the loans
Total Loans	67,542	67,204
Consumer construction
Composition of the loans
Total Loans	6,421	4,551
Commercial
Composition of the loans
Portfolio loans, net of unearned income	4,561,526	4,503,594
Commercial \| Commercial real estate
Composition of the loans
Portfolio loans, net of unearned income	2,826,372	2,685,994
Commercial \| Commercial and industrial
Composition of the loans
Portfolio loans, net of unearned income	1,451,371	1,433,266
Commercial \| Commercial construction
Composition of the loans
Portfolio loans, net of unearned income	283,783	384,334
Consumer
Composition of the loans
Portfolio loans, net of unearned income	1,246,281	1,257,855
Consumer \| Residential mortgage
Composition of the loans
Portfolio loans, net of unearned income	699,867	698,774
Consumer \| Home equity
Composition of the loans
Portfolio loans, net of unearned income	472,451	487,326
Consumer \| Installment and other consumer
Composition of the loans
Portfolio loans, net of unearned income	67,542	67,204
Consumer \| Consumer construction
Composition of the loans
Portfolio loans, net of unearned income	$ 6,421	$ 4,551

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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://fasb.org/us-gaap/role/ref/legacyRef
-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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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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Amount after allowance and 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. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
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