Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Loss Contingencies [Line Items]
Selling & administrative	$ 10,387,000	$ 8,218,000	$ 30,054,000	$ 24,536,000
Operating income (loss)	8,115,000	10,456,000	41,581,000	30,805,000
Directors and Officers Liability Insurance | Minimum
Loss Contingencies [Line Items]
Expenses that are subject to insurance reimbursement, collection period			90
Directors and Officers Liability Insurance | Maximum
Loss Contingencies [Line Items]
Expenses that are subject to insurance reimbursement, collection period			120
Legal Fees and Other Third Party Costs
Loss Contingencies [Line Items]
Selling & administrative	3,500,000	1,100,000	7,200,000	3,400,000
Legal Fees and Other Third Party Costs | Directors and Officers Liability Insurance
Loss Contingencies [Line Items]
Reimbursement from insurance carrier	2,800,000	1,000,000	5,700,000	3,000,000
Operating income (loss)	$ 700,000	$ 100,000	$ 1,500,000	$ 400,000