Loans and Allowance - Changes in Allowance for Loan Losses by Loan Segment (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Allowance for loan losses:
Beginning balance	$ 62,453	$ 63,964
Provision for losses	550
Recoveries on loans	1,634	$ 1,072
Loans charged off	(2,551)	(2,235)
Ending balance	62,086	62,801
Commercial
Allowance for loan losses:
Beginning balance	26,478	28,824
Provision for losses	139	1,834
Recoveries on loans	292	450
Loans charged off	(645)	(1,101)
Ending balance	26,264	30,007
Commercial Real Estate
Allowance for loan losses:
Beginning balance	22,145	19,327
Provision for losses	214	(2,896)
Recoveries on loans	952	412
Loans charged off	(994)	(460)
Ending balance	22,317	16,383
Consumer
Allowance for loan losses:
Beginning balance	2,689	2,658
Provision for losses	33	527
Recoveries on loans	78	78
Loans charged off	(153)	(125)
Ending balance	2,647	3,138
Residential
Allowance for loan losses:
Beginning balance	11,139	13,152
Provision for losses	164	534
Recoveries on loans	312	132
Loans charged off	(759)	(549)
Ending balance	10,856	13,269
Finance Leases
Allowance for loan losses:
Beginning balance	$ 2	3
Provision for losses		$ 1
Recoveries on loans
Loans charged off
Ending balance	$ 2	$ 4

Allowance for Loan and Lease Losses, Loan Recoveries

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- Definition

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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- Definition

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

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 6
-Section L
-Subsection 1

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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