Key Assumptions Used in Calculating Fair Value of Residential Mortgage Servicing Rights (Detail) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Mortgage Loans on Real Estate [Line Items]
Expected Weighted Average Life	83 months	83 months
Constant Prepayment Speed	10.50%	9.30%
Discount Rate	10.00%	10.00%
Primary Mortgage Rate to Refinance	3.80%	4.00%
Current
Mortgage Loans on Real Estate [Line Items]
Cost to service per loan per year	63	63
30-59 days or less delinquent
Mortgage Loans on Real Estate [Line Items]
Cost to service per loan per year	213	213
60-89 days delinquent
Mortgage Loans on Real Estate [Line Items]
Cost to service per loan per year	313	313
90-119 days delinquent
Mortgage Loans on Real Estate [Line Items]
Cost to service per loan per year	413	413
120 days or more delinquent
Mortgage Loans on Real Estate [Line Items]
Cost to service per loan per year	563	563

Cost to service per loan per year.

No definition available.

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- Definition

Discount rate which is used to value residual cash flows generated by financial assets of a securitization, asset-backed financing arrangement, or similar transfer regardless of when the transfer occurred.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

+ Details

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- Definition

The stated interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule IV)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 29

-Article 12

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule IV

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-29)

-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

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- Definition

Estimated rate of prepayments of principal on servicing assets and servicing liabilities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 50

-Section 50

-Paragraph 2

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7882072&loc=d3e122596-111746

+ Details

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- Definition

Weighted average life of financial assets and financial liabilities, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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