Loans - Allowance for Loan Losses (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2012	Dec. 31, 2011
Allowance for loan losses:
Allowance for loan losses, beginning of period	$ 25,596	$ 26,934
Provision for loan losses	11,750	20,500
Loan charge-offs	19,895	22,832
Loan recoveries	887	994
Net loans charged-off	19,008	21,838
Allowance for loan losses, end of period	18,338	25,596
Individually evaluated for impairment	3,442	6,505
Collectively evaluated for impairment	14,896	19,091
Gross loans, end of period:
Total gross loans	733,940	773,558
Loans Receivable [Member]
Allowance for loan losses:
Allowance for loan losses, end of period	18,338	25,596
Gross loans, end of period:
Individually evaluated for impairment	40,752	69,791
Collectively evaluated for impairment	693,188	703,767
Total commercial real estate [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	18,026
Provision for loan losses	10,126
Loan charge-offs	15,495
Loan recoveries	170
Net loans charged-off	15,325
Allowance for loan losses, end of period	12,827
Individually evaluated for impairment	3,127
Collectively evaluated for impairment	9,700
Gross loans, end of period:
Total gross loans	451,384	492,754
Total commercial real estate [Member] \| Loans Receivable [Member]
Allowance for loan losses:
Allowance for loan losses, end of period	12,827
Gross loans, end of period:
Individually evaluated for impairment	35,486
Collectively evaluated for impairment	415,898
Total single-family residential loans [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	4,488
Provision for loan losses	1,689
Loan charge-offs	3,044
Loan recoveries	94
Net loans charged-off	2,950
Allowance for loan losses, end of period	3,227
Individually evaluated for impairment	261
Collectively evaluated for impairment	2,966
Gross loans, end of period:
Total gross loans	170,143
Total single-family residential loans [Member] \| Loans Receivable [Member]
Allowance for loan losses:
Allowance for loan losses, end of period	3,227
Gross loans, end of period:
Individually evaluated for impairment	3,746
Collectively evaluated for impairment	166,397
Commercial and Industrial [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	1,862
Provision for loan losses	(426)
Loan charge-offs	361
Loan recoveries	133
Net loans charged-off	228
Allowance for loan losses, end of period	1,208
Individually evaluated for impairment	49
Collectively evaluated for impairment	1,159
Gross loans, end of period:
Total gross loans	51,921
Commercial and Industrial [Member] \| Loans Receivable [Member]
Allowance for loan losses:
Allowance for loan losses, end of period	1,208
Gross loans, end of period:
Individually evaluated for impairment	1,481
Collectively evaluated for impairment	50,440
Consumer [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	1,209
Provision for loan losses	218
Loan charge-offs	498
Loan recoveries	145
Net loans charged-off	353
Allowance for loan losses, end of period	1,074
Individually evaluated for impairment	5
Collectively evaluated for impairment	1,069
Gross loans, end of period:
Total gross loans	51,371
Consumer [Member] \| Loans Receivable [Member]
Allowance for loan losses:
Allowance for loan losses, end of period	1,074
Gross loans, end of period:
Individually evaluated for impairment	39
Collectively evaluated for impairment	51,332
Other [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	11
Provision for loan losses	143
Loan charge-offs	497
Loan recoveries	345
Net loans charged-off	152
Allowance for loan losses, end of period	2
Collectively evaluated for impairment	2
Gross loans, end of period:
Total gross loans	9,121
Other [Member] \| Loans Receivable [Member]
Allowance for loan losses:
Allowance for loan losses, end of period	2
Gross loans, end of period:
Collectively evaluated for impairment	$ 9,121

Allowance for loan and lease losses write offs net of recoveries.

No definition available.

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- Definition

Reflects the gross amount charged against earnings during the period as credit losses (bad debt expense) based on review of the loan and lease portfolio and application of the methodology for estimating credit losses.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Name Regulation S-X (SX)

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-Section 03

-Paragraph 7

-Subparagraph d

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- Definition

Reflects a reduction in bad debt expense attributable to collections of loans and lease receivables which had previously been fully or partially charged off as bad debts.

+ References

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- Definition

Reflects the amount of loans and leases that have been removed, or charged off, from both loan receivables and the reserve for credit losses, typically because they are considered to be not salvageable or have been purchased by unconsolidated collection entities.

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

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- Definition

The balance of financing receivables that were individually evaluated for impairment.

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 8, 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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-Publisher AICPA

-Name Statement of Position (SOP)

-Number 01-6

-Paragraph 13

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