Deposits - Summary of Interest Expense on Deposits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Banking and Thrift [Abstract]
Interest-bearing checking accounts	$ 925	$ 1,408	$ 2,878
Money market deposit accounts	92	165	361
Savings accounts	112us-gaap_InterestExpenseSavingsDeposits	187us-gaap_InterestExpenseSavingsDeposits	359us-gaap_InterestExpenseSavingsDeposits
Time deposits	2,974us-gaap_InterestExpenseTimeDeposits	2,949us-gaap_InterestExpenseTimeDeposits	3,949us-gaap_InterestExpenseTimeDeposits
Interest expense on deposits	$ 4,103us-gaap_InterestExpenseDeposits	$ 4,709us-gaap_InterestExpenseDeposits	$ 7,547us-gaap_InterestExpenseDeposits

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Aggregate amount of interest expense on all deposits.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.6)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 6

-Article 9

+ Details

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- Definition

Interest expense incurred on all money market deposits.

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+ Details

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- Definition

Interest expense incurred on the amount of Negotiable Order of Withdrawal (NOW). Interest-bearing transaction account that combines the payable on demand feature of checks and investment feature of savings accounts. A NOW account is functionally an interest paying checking account.

+ References

+ Details

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- Definition

Interest expense incurred on all savings account deposits.

+ References

+ Details

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- Definition

The aggregate interest expense incurred on time deposits, including certificates of deposits, in domestic offices.

+ References

+ Details

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