Capital Stock - Additional Information (Detail) (USD $)	12 Months Ended							12 Months Ended			1 Months Ended			1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Series A Preferred Stock	Dec. 31, 2011 Series A Preferred Stock	Dec. 31, 2012 Series B Preferred Stock	Dec. 31, 2011 Series B Preferred Stock	Dec. 31, 2012 Restricted Stock Non Employee Director	Dec. 31, 2011 Restricted Stock Non Employee Director	Dec. 31, 2010 Restricted Stock Non Employee Director	Mar. 12, 2013 Subsequent Event	Dec. 31, 2012 Long Term Incentive Plan 2000	Jun. 30, 2012 Long Term Incentive Plan 2000 After Amendment	Jun. 30, 2012 Long Term Incentive Plan 2000 Minimum	Jun. 30, 2012 Long Term Incentive Plan 2000 Maximum	Jun. 30, 2012 Long Term Incentive Plan 2000 Increase
Share Based Compensation [Line Items]
Shares available for grant												756,832	4,200,000			700,000
Options expiration period														5 years	10 years
Options vesting period									1 year						5 years
Date declared											$ 0.03125
Dividend payable date											May 15, 2013
Dividends declare, Date of Record											May 01, 2013
Preferred stock, shares authorized				100	100	2,000,000	2,000,000
Preferred stock, issued
Preferred stock, outstanding
Total number of restricted shares issued								23,394	21,400	10,020
Total fair value of the restricted shares								$ 270,000	$ 230,000	$ 150,000
Total intrinsic value of stock options exercised	1,182,000	830,400	389,100
Stock compensation expense	2,793,000	2,795,000	2,928,000
Unrecognized share based compensation expenses	$ 4,100,000
Weighted-average recognition period	1 year 9 months 7 days
Weighted-average per share grant date fair value of stock options granted	$ 6.05	$ 5.69	$ 7.96