Long Term Obligation - Long-Term Debt is Carried at Amortized Cost Long-Term Obligations (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Long term debt	$ 4,057,594	$ 4,017,656
Less: current maturities	(470,159)	(25,125)
Long-term obligations	3,587,435	3,992,531
11% Senior Subordinated Notes, called April 26, 2013 [Member]
Debt Instrument [Line Items]
Long term debt	450,000	450,000
Asset Securitization Facility, due 2014 [Member]
Debt Instrument [Line Items]
Long term debt	50,000
Senior Secured Term Loan Facility, due 2016 [Member]
Debt Instrument [Line Items]
Long term debt	316,862	1,452,506
Senior Secured Term Loan Facility, due 2018 [Member]
Debt Instrument [Line Items]
Long term debt	2,090,732	965,150
8 5/8% Senior Notes, due 2018 [Member]
Debt Instrument [Line Items]
Long term debt	500,000	500,000
7 7/8% Senior Notes, due 2019 [Member]
Debt Instrument [Line Items]
Long term debt	$ 650,000	$ 650,000