Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended		12 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2013 Unrecognized Tax Positions	Sep. 30, 2012 Estimated Effective Income Tax Rate
Income Tax Contingency
Refund of Federal Tax and Interest		$ 1,626,000	$ 1,060,000
Reversal of valuation allowance	(3,644,000)
Consolidated overall estimated effective income tax rate					22.70%
Consolidated overall estimated effective income tax rate		23.00%
Refund received on Settlement with Taxing Authority			1,730,000
Estimated unrecognized tax benefits as a result of tax position taken in prior years		19,527,000		9,007,000
Unrecognized tax benefits that would impact effective tax rate	$ 6,546,000	$ 6,546,000