Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income tax provision	$ 1,037,000	$ 750,000	$ 4,941,000	$ 2,654,000
Liability for income taxes associated with uncertain tax positions	8,484,000		8,484,000
Tax benefits associated with potential transfer pricing adjustments			2,798,000
Tax benefits associated with state income taxes	3,063,000		3,063,000
Net amount of unrecognized tax benefit related to uncertain tax positions that would impact, if recognized, effective income tax rate	2,623,000		2,623,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	1,904,000		1,904,000
Interest and penalties related to income tax matters	58,000	61,000	150,000	29,000
Income tax accrued for payment of interest and penalties	$ 920,000		$ 920,000		$ 1,245,000