Long-Term Obligations - Schedule of Long-Term Obligations (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Long Term Debt Current And Noncurrent [Line Items]
Long-term obligations	$ 457,647	$ 555,400
Less current portion	(12,865)	(21,628)
Long-term obligations, net of current portion	444,782	533,772
2010 Senior Credit Facility Term Loan Due 2016 [Member]
Long Term Debt Current And Noncurrent [Line Items]
Long-term obligations	347,725	431,200
Debt instrument unamortized discount	(1,838)	(2,796)
6.25% Convertible Notes Due 2018 [Member]
Long Term Debt Current And Noncurrent [Line Items]
Long-term obligations	114,000	120,000
Debt instrument unamortized discount	(9,666)	(11,602)
5.75% Convertible Notes Due 2013 [Member]
Long Term Debt Current And Noncurrent [Line Items]
Long-term obligations		12,980
Debt instrument unamortized discount		(114)
Revolving Credit Facility Loan [Member]
Long Term Debt Current And Noncurrent [Line Items]
Revolving credit facility loan
Capital Leases and Other Long-Term Obligations [Member]
Long Term Debt Current And Noncurrent [Line Items]
Long-term obligations	$ 7,426	$ 5,732