Fair Values of Assets and Liabilities - Valuation Assumption Ranges for MSRs (Detail) - Mortgage Servicing Rights [Member]	12 Months Ended
Dec. 31, 2016
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	6.00%
Option adjusted spread	7.00%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	18.00%
Option adjusted spread	10.00%
Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	10.00%
Option adjusted spread	8.00%

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No definition available.

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value.

+ References

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