Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Tax Disclosure [Abstract]
Income tax benefit	$ 4,279	$ 2,074	$ 7,321	$ 4,978
Effective income tax rate	42.10%	61.30%	44.10%	51.50%
U.S. federal statutory rate	35.00%		35.00%