Loans Held for Sale and Loan Servicing Narrative Data (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Servicing Assets at Fair Value [Line Items]
Unpaid principal balance of loans serviced for others	$ 452,000,000	$ 422,300,000
Loan servicing rights, unamortized balance	1,600,000	1,500,000
Loan servicing rights, valuation allowance	0	0
Credit Enhancement Obligation [Member]
Servicing Assets at Fair Value [Line Items]
Contractual risk sharing commitments, maximum liability	$ 634,000	$ 595,000

Unpaid principal balance of loans not included on the balance sheet that are serviced for others.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

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+ Details

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- Definition

Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7524895&loc=d3e120260-111741

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
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-Publisher FASB
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+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=56950315&loc=d3e122739-111746

+ Details

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Balance Type:	credit
Period Type:	instant

- Details

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