Stock Incentive Plans - Additional Information (Detail) (USD $)	12 Months Ended			12 Months Ended	1 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Restricted Stock	Aug. 31, 2012 2012 Plan	Dec. 31, 2012 2012 Plan	Dec. 31, 2012 2012 Plan Restricted Stock	Dec. 31, 2011 2012 Plan Restricted Stock	Aug. 31, 2012 Previously Approved Plans	Dec. 31, 2012 Previously Approved Plans	Dec. 31, 2011 Previously Approved Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares initially authorized for issuance under equity incentive plan					300,000
Additional shares authorized for issuance under equity incentive plan					17,666
Shares ceased to be issuable									17,666
Outstanding options to purchase shares of common stock	433,000	546,001	652,001
Unvested restricted shares outstanding				312,501
Outstanding shares remained available for future grants						323,833
Aggregate pre-tax intrinsic value	$ 3,000	$ 21,000
Weighted average fair value of options granted	$ 1.28	$ 1.97
Unrecognized compensation cost related to the nonvested service-conditioned restricted shares										3,000	8,550
Expected to be recognized over a weighted average period				1 year 7 months 6 days						2 months 12 days	6 months
Common stock to be Awarded							147,500	114,500
Unrecognized stock-based compensation cost attributable to these restricted shares				578,000
Aggregate intrinsic value	$ 157,000	$ 202,800		$ 625,000