Finance Receivables and Allowance for Credit Losses - Schedule of Average Balance and Interest Income Recognized on Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Average Recorded Investment, Total	$ 68,185	$ 71,200
Interest Income Recognized	1,371	656
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment with no related allowance	21,592	11,815
Interest Income Recognized with no related allowance	325	135
Average Recorded Investment with an allowance recorded	7,579	16,351
Interest Income Recognized with an allowance recorded	94	123
Commercial Real Estate - Construction [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment with no related allowance	1,347	852
Interest Income Recognized with no related allowance	69
Average Recorded Investment with an allowance recorded	49	1,614
Interest Income Recognized with an allowance recorded	4
Commercial Real Estate - Other [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment with no related allowance	21,560	16,345
Interest Income Recognized with no related allowance	328	140
Average Recorded Investment with an allowance recorded	12,160	22,317
Interest Income Recognized with an allowance recorded	409	134
Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment with no related allowance	505	138
Interest Income Recognized with no related allowance	14	10
Average Recorded Investment with an allowance recorded	1,189	526
Interest Income Recognized with an allowance recorded	58	40
Residential [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment with no related allowance	347	62
Interest Income Recognized with no related allowance	1	1
Average Recorded Investment with an allowance recorded	1,857	1,180
Interest Income Recognized with an allowance recorded	$ 69	$ 73

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

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- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

+ References

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- Definition

Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

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- Definition

Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

+ References

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