Fair Value Measurement (Details 3) (USD $)		3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Senior secured revolving credit facility	Mar. 31, 2012 8.25% Senior subordinated notes due 2016	Mar. 31, 2012 10.25% Senior notes due 2014, net of unamortized discount	Dec. 31, 2011 10.25% Senior notes due 2014, net of unamortized discount	Mar. 31, 2012 6.75% Senior notes due 2020	Mar. 31, 2012 Senior Notes 6.375% Due 2022	Mar. 09, 2012 Senior Notes 6.375% Due 2022	Mar. 31, 2012 Cash and cash equivalents		Mar. 31, 2012 Level 1	Mar. 31, 2012 Level 1 Cash and cash equivalents		Mar. 31, 2012 Carrying Amount	Dec. 31, 2011 Carrying Amount	Mar. 31, 2012 Carrying Amount Senior secured revolving credit facility		Dec. 31, 2011 Carrying Amount Senior secured revolving credit facility	Mar. 31, 2012 Carrying Amount 8.25% Senior subordinated notes due 2016	Dec. 31, 2011 Carrying Amount 8.25% Senior subordinated notes due 2016	Mar. 31, 2012 Carrying Amount 10.25% Senior notes due 2014, net of unamortized discount		Dec. 31, 2011 Carrying Amount 10.25% Senior notes due 2014, net of unamortized discount		Mar. 31, 2012 Carrying Amount 6.75% Senior notes due 2020	Dec. 31, 2011 Carrying Amount 6.75% Senior notes due 2020	Mar. 31, 2012 Carrying Amount Senior Notes 6.375% Due 2022	Mar. 31, 2012 Carrying Amount Cash and cash equivalents		Dec. 31, 2011 Estimated Fair Value	Mar. 31, 2012 Estimated Fair Value Senior secured revolving credit facility		Dec. 31, 2011 Estimated Fair Value Senior secured revolving credit facility	Mar. 31, 2012 Estimated Fair Value 8.25% Senior subordinated notes due 2016	Dec. 31, 2011 Estimated Fair Value 8.25% Senior subordinated notes due 2016	Mar. 31, 2012 Estimated Fair Value 10.25% Senior notes due 2014, net of unamortized discount		Dec. 31, 2011 Estimated Fair Value 10.25% Senior notes due 2014, net of unamortized discount		Mar. 31, 2012 Estimated Fair Value 6.75% Senior notes due 2020	Dec. 31, 2011 Estimated Fair Value 6.75% Senior notes due 2020	Mar. 31, 2012 Estimated Fair Value Senior Notes 6.375% Due 2022	Mar. 31, 2012 Estimated Fair Value Level 1 Senior secured revolving credit facility		Mar. 31, 2012 Estimated Fair Value Level 1 8.25% Senior subordinated notes due 2016	Mar. 31, 2012 Estimated Fair Value Level 1 10.25% Senior notes due 2014, net of unamortized discount		Mar. 31, 2012 Estimated Fair Value Level 1 6.75% Senior notes due 2020	Mar. 31, 2012 Estimated Fair Value Level 1 Senior Notes 6.375% Due 2022	Mar. 31, 2012 Estimated Fair Value Level 2 Senior secured revolving credit facility
Fair value and carrying value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure									$ 44,000,000	[1]		$ 44,000,000	[1]															$ 44,000,000	[1]
Debt Instrument, Fair Value Disclosure	1,599,000,000										1,599,000,000			1,499,000,000	1,387,000,000	0	[2]	531,500,000	200,000,000	200,000,000	355,000,000	[3]	355,000,000	[4]	300,000,000	300,000,000	600,000,000			1,445,000,000	0	[2]	531,500,000	209,000,000	209,000,000	409,000,000	[3]	402,000,000	[4]	319,000,000	302,000,000	618,000,000	0	[2]	209,000,000	409,000,000	[3]	319,000,000	618,000,000		[2]
Interest rate on debt instrument (as a percent)			8.25%	10.25%		6.75%	6.375%	6.375%
Unamortized discount				$ 5,966,000	$ 6,564,000
Fixed interest rate increments (in days)		30 days

[1] Consists primarily of money market mutual funds.

[2] The Company's secured revolving credit facility can be repaid at any time without penalty. Interest is generally fixed for 30-day increments at the prime rate or LIBOR plus a stipulated margin for the amount utilized and at a stipulated percentage as a commitment fee for the portion not utilized. The Company uses a market approach to ensure the terms of its credit facility are in line with market rates for similar credit facilities, which are considered to be level 2 inputs.

[3] Carrying amount does not include unamortized discount of $6.0 million.

[4] Carrying amount does not include unamortized discount of $6.6 million.