Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2009	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income Taxes [Line Items]
Net deferred tax (Liabilities) assets		$ (169)	$ (120)	$ 863
Valuation allowance		5,244	5,078	9,301
Change in valuation allowance			4,223
Received refund from the IRS	40,418
Amount of refund claim up to which IRS examination team is required by statute to review all refund					2,000
Adjustment to Taxable Income					13,700
Taxes owed					4,806
Accrued interest		542
Income tax expense		5,348
Tax and interest						1,400
Tax and interest accrued		800
Reversal of Income Tax Receivable				2,200
Recognized tax expenses				1,400
Reversal of receivable				1,400
Reversal of prior tax expense				2,200
Reversal of tax benefit accrual				$ 800