Securities - Additional Information Concerning Company's Investments in Corporate Debt Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 10,545
Estimated Fair Value	10,328
Average Maturity (years)	12 years 7 months 6 days
Average Book Yield	6.46%
Subordinated Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,438
Estimated Fair Value	3,768
Average Maturity (years)	3 years 9 months 18 days
Average Book Yield	6.16%
PREFERRED STOCK [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,107
Estimated Fair Value	$ 6,560
Average Maturity (years)	16 years 10 months 24 days
Average Book Yield	6.61%

Amount of available-for-sale debt securities at cost, net of adjustments, which include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

+ References

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