Certain Transfers of Financial Assets - SBA Loan Servicing Rights and Impairment (Details) - SBA servicing rights - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
SBA Loan Servicing Rights [Rollforward]
Beginning carrying value, net	$ 5,707	$ 5,358
Additions	1,240	1,669
Amortization	(1,995)	(1,563)
(Impairment) recovery, net	(134)	243
Ending carrying value, net	4,818	5,707
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Beginning balance	0	243
Additions	134	0
Recoveries	0	(243)
Ending balance	$ 134	$ 0

SBA Loan Servicing Rights

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- Definition

Amount of other-than-temporary impairment (OTTI) applied to 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 50
-Paragraph 4
-Subparagraph (a)(6)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122739-111746

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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
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- Definition

Amount of additions from purchases, assumption or transfer to 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
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- Definition

Amount of amortization 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
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- 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
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-SubTopic 50
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-Paragraph 4
-Subparagraph (e)(1)
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- Definition

Amount of increase in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from charges to expense.

+ References

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-Publisher FASB
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- Definition

Amount of decrease in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from recoveries recognized.

+ References

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-Publisher FASB
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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.

+ References

No definition available.

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