Federal Home Loan Bank Borrowings - Summary of Contractual Maturities of FHLB borrowings (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Advances From Federal Home Loan Banks [Abstract]
Due in 2013	$ 23,116
Due in 2014	95,267
Due in 2015	99,919
Due in 2016	104,800
Due in 2017	109,918
Due in 2018 and thereafter	3,105,675
Total	$ 3,538,695	$ 3,606,411

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Amount of federal home loan bank advances maturing after the fifth fiscal year following the latest fiscal year.

+ 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 FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of federal home loan bank advances maturing in the fifth fiscal year following the latest fiscal year.

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Amount of federal home loan bank advances maturing in the second fiscal year following the latest fiscal year.

+ References

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Amount of federal home loan bank advances maturing in the fourth fiscal year following the latest fiscal year.

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Amount of federal home loan bank advances maturing in the third fiscal year following the latest fiscal year.

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Amount of federal home loan bank advances maturing in the remainder of the fiscal year following the latest fiscal year ended.

+ References

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