Stock-Based Employee Compensation Plans - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding	1,469,847	1,469,847	1,138,241	1,153,741	1,177,642
Options exercised	128	5,328
Fair value of options vested		$ 158,300.000	$ 55.000
Aggregate intrinsic values of options outstanding and exercisable	1,200,000	1,200,000	146,000
Aggregate amounts of stock based compensation expense, net of taxes		$ 132,000	$ 106,000
Nonvested awards, expected weighted average recognition period		1 year 117 days
Equity Incentive Plan 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant or awarding of equity incentives	400,000	400,000
Shares ceased to be issuable under Previously Approved Plans and become available for grant or awarding of equity incentives under current plan		158,211
Maximum number of shares that could be issued pursuant to equity incentives assuming all options outstanding under Previously Approved Plans were to expire or be canceled	1,699,227	1,699,227
Previously Approved Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding	1,493,465	1,493,465
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price per share of common stock as percentage of fair market value of shares on respective grant dates of stock options		100.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, restricted shares and SARs, vesting period		5 years
Options and SARs, terms after date of grant		10 years