Loans and the Allowance for Loan Losses - (Details Textual)	3 Months Ended	12 Months Ended
Mar. 31, 2016 USD ($) loan_grade loan	Dec. 31, 2015 USD ($) loan
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Mortgage and commercial loans discontinued past due period (in days)	90 days
Consumer and other retail loans charged-off past due period (in days)	120 days
Nonperforming loans charged-off past due period (in days)	90 days
Number of restructured loans \| loan	2	2
Restructured loans discontinued past due period (in days)	90 days	90 days
Allowance for loan losses attributable to restructured loans	$ 42,859,000	$ 42,437,000
Remaining availability under commitments to lend additional funds on restructured loans	0	0
Fair value of loans contractual principal cash flows amount	82,618,000
Fair value of loans contractual interest cash flows	201,000
Fair value of loans contractual interest payments	2,278,000
Fair value of loans contractual purchase discount	$ 43,603,000
Watch
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	5
Maximum
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	9
Maximum \| Pass
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	4
Maximum \| Substandard
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	9
Minimum
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	1
Minimum \| Pass
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	1
Minimum \| Substandard
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade	6
Nonaccruing Loans
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Outstanding balance of restructured loans	$ 136,000	0
Restructured Loans
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Outstanding balance of restructured loans	13,000	14,000
Allowance for loan losses attributable to restructured loans	$ 1,010,000	$ 979,000

Consumer and other retail loans charged off past due period.

No definition available.

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- Definition

Fair value of loans contractual interest cash flows.

+ References

No definition available.

+ Details

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- Definition

Fair value of loans contractual principal cash flows amount.

+ References

No definition available.

+ Details

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- Definition

Fair value of loans contractual purchase discount.

+ References

No definition available.

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- Definition

Fair value of loans future interest payments.

+ References

No definition available.

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- Definition

Loan grades range.

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No definition available.

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- Definition

Loans and the allowance for loan losses.

+ References

No definition available.

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- Definition

Mortgage and commercial loans discontinued past due period.

+ References

No definition available.

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- Definition

Nonperforming loans charged off past due period.

+ References

No definition available.

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- Definition

Number of Restructured Loans

+ References

No definition available.

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- Definition

Maximum duration past due for restructured loans to be considered performing.

+ References

No definition available.

+ Details

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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=66008989&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=66008989&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 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 5: 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

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- Definition

Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18794-111554

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- Definition

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://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(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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