Borrowings - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Credit available with FHLB	$ 3,840,436
Credit with FHLB used	$ 850,056
Federal Home Loan Bank advances are scheduled to mature periodically through the year	2021
Effective interest rates, minimum	0.26%	1.06%
Effective interest rates, maximum	4.19%	4.19%

Amount of advances or credit lines used from the Federal Home Loan Bank (FHLB).

No definition available.

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- Details

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- Definition

The last year of maturity for the advances from the Federal Home Loan Bank as of the Balance Sheet date.

+ References

+ Details

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- Definition

States the lowest interest rate applicable to any of the advances from the Federal Home Loan Bank as of the Balance Sheet date.

+ References

+ Details

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- Definition

States the highest interest rate applicable to any of the advances from the Federal Home Loan Bank as of the Balance Sheet date.

+ References

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- Definition

Amount of maximum advances or credit lines available from the Federal Home Loan Bank (FHLB).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Subparagraph b

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(3)(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22 (b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 3(a)

-Article 9

+ Details

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