Long-Term Debt - Summary of Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Debt Disclosure [Abstract]
Notes, Carrying Value	$ 0	$ 15,000
Notes, Fair Value	0	15,000
Senior Secured Notes, Carrying Value	305,000	0
Senior Secured Notes, Fair Value	299,663	0
Credit Agreement, Carrying Value	535,000	0
Credit Agreement, Fair Value	535,000	0
Convertible Notes, Carrying Amount	117,259	0
Convertible Notes, Fair Value	117,845	0
Total, Carrying Amount	957,259	15,000
Total, Fair Value	952,508	15,000
Less: Current portion recorded in Accrued expenses and other liabilities, Carrying Amount	235,000	0
Less: Current portion recorded in Accrued expenses and other liabilities, Fair Value	235,000	0
Total Long-term debt, Carrying Amount	722,259	15,000
Total Long-term debt, Fair Value	$ 717,508	$ 15,000