Debt (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended						12 Months Ended			0 Months Ended				1 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 27, 2014	Sep. 27, 2013	Nov. 21, 2012	Mar. 27, 2013	Mar. 31, 2013	Apr. 01, 2011	Jul. 14, 2014
Debt instrument
Total Debt	$ 3,135,970,000						$ 3,135,970,000	$ 2,778,832,000
Debt discount	(18,293,000)						(18,293,000)	(20,788,000)
Less current debt	(12,327,000)						(12,327,000)	(9,210,000)
Total long-term debt	3,123,643,000						3,123,643,000	2,769,622,000
Payments Due
2015	12,327,000						12,327,000
2016	5,758,000						5,758,000
2017	0						0
2018	978,178,000						978,178,000
2019	970,000,000						970,000,000
Thereafter	1,188,000,000						1,188,000,000
Gain (loss) on partial extinguishment of debt								(13,900,000)
Proceeds from debt							869,800,000	897,412,000	496,510,000
Gain resulting from transaction	32,800,000	3,400,000	11,400,000	(13,900,000)	(900,000)	6,000,000	33,673,000	(6,875,000)	(5,555,000)
Prior to April 1, 2017
Payments Due
Debt instrument, make-whole premium										1.625%
2011 term loan A
Debt instrument
Total Debt	0						0	406,566,000
Debt discount								(5,514,000)
Weighted average stated interest rate (as a percent)	0.00%						0.00%
Payments Due
Aggregate principal amount															950,000,000
Gain (loss) on partial extinguishment of debt								1,000,000
Extinguishment of debt											250,000,000
2011 term loan B
Debt instrument
Total Debt	978,178,000						978,178,000	978,178,000
Debt discount	(11,895,000)						(11,895,000)	(9,597,000)
Weighted average stated interest rate (as a percent)	7.25%						7.25%
Payments Due
2015	0						0
2016	0						0
2017	0						0
2018	978,178,000						978,178,000
2019	0						0
Thereafter	0						0
Aggregate principal amount															1,400,000,000
Increase in interest rate (as a percent)							0.50%
Basis spread on variable rate (as a percent)							6.25%
2011 term loan B | Minimum
Payments Due
Rate of LIBOR floor (as a percent)	1.00%						1.00%
9.50% senior secured notes
Debt instrument
Total Debt	970,000,000						970,000,000	450,000,000
Debt discount	(2,651,000)						(2,651,000)	(2,508,000)
Weighted average stated interest rate (as a percent)	9.50%						9.50%
Payments Due
2015	0						0
2016	0						0
2017	0						0
2018	0						0
2019	970,000,000						970,000,000
Thereafter	0						0
Aggregate principal amount										200,000,000	450,000,000					320,000,000
Interest rate (as a percent)										9.50%	9.50%					9.50%
Proceeds from debt											245,700,000
Redemption price of debt instrument (as a percent)							101.00%
9.50% senior secured notes | Up to 35% redeemable prior to October 15, 2016
Payments Due
Redemption price of debt instrument (as a percent)							109.50%
9.50% senior secured notes | Prior to October 15, 2016
Payments Due
Redemption price of debt instrument (as a percent)							100.00%
9.50% senior secured notes | During the twelve months commencing October 15, 2016
Payments Due
Redemption price of debt instrument (as a percent)							107.125%
9.50% senior secured notes | During the twelve months commencing October 15, 2017
Payments Due
Redemption price of debt instrument (as a percent)							102.375%
9.50% senior secured notes | Period commencing October15, 2018
Payments Due
Redemption price of debt instrument (as a percent)							100.00%
9.50% senior secured notes | Maximum | Up to 35% redeemable prior to October 15, 2016
Payments Due
Aggregate principal of debt redeemed (as a percent)	35.00%						35.00%
11.0%/12.0% senior secured PIK toggle notes
Debt instrument
Total Debt	350,000,000						350,000,000	0
Payments Due
2015	0						0
2016	0						0
2017	0						0
2018	0						0
2019	0						0
Thereafter	350,000,000						350,000,000
Aggregate principal amount										350,000,000
Redemption price of debt instrument (as a percent)							101.00%			111.00%
Percentage of interest that may be paid in cash										50.00%
Percentage of interest that may be paid by increasing principal or issuing new debt										50.00%
Percentage of paid in kind interest that may be paid in cash										75.00%
Percentage of paid in kind interest that may be paid by increasing principal or issuing new debt										25.00%
11.0%/12.0% senior secured PIK toggle notes | Prior to April 1, 2017
Payments Due
Redemption price of debt instrument (as a percent)										100.00%
11.0%/12.0% senior secured PIK toggle notes | During the twelve months commencing April 1, 2017
Payments Due
Redemption price of debt instrument (as a percent)										105.50%
11.0%/12.0% senior secured PIK toggle notes | During the twelve months commencing April 1, 2018
Payments Due
Redemption price of debt instrument (as a percent)										102.75%
11.0%/12.0% senior secured PIK toggle notes | Beginning April 1, 2019 [Member]
Payments Due
Redemption price of debt instrument (as a percent)										100.00%
11.0%/12.0% senior secured PIK toggle notes | Minimum
Debt instrument
Weighted average stated interest rate (as a percent)	11.00%						11.00%			11.00%
11.0%/12.0% senior secured PIK toggle notes | Maximum
Debt instrument
Weighted average stated interest rate (as a percent)	12.00%						12.00%			12.00%
Payments Due
Aggregate principal of debt redeemed (as a percent)										35.00%
9.875% senior notes
Debt instrument
Total Debt	388,000,000						388,000,000	500,000,000
Debt discount	(2,205,000)						(2,205,000)	(3,169,000)
Weighted average stated interest rate (as a percent)	9.88%						9.88%
Payments Due
2015	0						0
2016	0						0
2017	0						0
2018	0						0
2019	0						0
Thereafter	388,000,000						388,000,000
Interest rate (as a percent)	9.875%						9.875%					9.875%
Redemption price of debt instrument (as a percent)												101.00%
Debt issued												500,000,000
Debt issuance price as a percentage of face amount												99.302%
Common stock exchanged for senior notes (in shares)							9.3
Cash exchanged for senior notes							5,200,000
Senior notes received in transaction							112,000,000
Gain resulting from transaction							54,100,000
Gain per basic and diluted share (in dollars per share)							$ 0.81
9.875% senior notes | Prior to December 15, 2015
Payments Due
Redemption price of debt instrument (as a percent)												109.875%
9.875% senior notes | Prior to December 15, 2016
Payments Due
Redemption price of debt instrument (as a percent)												100.00%
9.875% senior notes | During the twelve months commencing December 15, 2016
Payments Due
Redemption price of debt instrument (as a percent)												104.938%
9.875% senior notes | During the twelve months commencing December 15, 2017
Payments Due
Redemption price of debt instrument (as a percent)												102.469%
9.875% senior notes | After December 15, 2018
Payments Due
Redemption price of debt instrument (as a percent)												100.00%
9.875% senior notes | Maximum | Prior to December 15, 2015
Payments Due
Aggregate principal of debt redeemed (as a percent)												35.00%
8.50% senior notes
Debt instrument
Total Debt	450,000,000						450,000,000	450,000,000
Weighted average stated interest rate (as a percent)	8.50%						8.50%
Payments Due
2015	0						0
2016	0						0
2017	0						0
2018	0						0
2019	0						0
Thereafter	450,000,000						450,000,000
Interest rate (as a percent)	8.50%						8.50%						8.50%
Redemption price of debt instrument (as a percent)													101.00%
Debt issued													450,000,000
8.50% senior notes | Prior to April 15, 2016
Payments Due
Redemption price of debt instrument (as a percent)													108.50%
8.50% senior notes | Prior to April 15, 2017
Payments Due
Redemption price of debt instrument (as a percent)													100.00%
8.50% senior notes | During the twelve months commencing April 15, 2017
Payments Due
Redemption price of debt instrument (as a percent)													104.25%
8.50% senior notes | During the twelve months commencing April 15, 2018
Payments Due
Redemption price of debt instrument (as a percent)														102.125%
8.50% senior notes | Period commencing April 15, 2019
Payments Due
Redemption price of debt instrument (as a percent)													100.00%
8.50% senior notes | Maximum | Prior to April 15, 2016
Payments Due
Aggregate principal of debt redeemed (as a percent)													35.00%
Other
Debt instrument
Total Debt	18,085,000						18,085,000	14,876,000
Payments Due
2015	12,327,000						12,327,000
2016	5,758,000						5,758,000
2017	0						0
2018	0						0
2019	0						0
Thereafter	0						0
2011 Credit Agreement - 2017
Payments Due
Maximum borrowing capacity	60,000,000						60,000,000								2,725,000,000
Percentage of revolving commitments with extended maturity date							81.60%
Commitment fee on the unused portion (as a percent)							0.625%
Availability for future borrowings under the revolver	9,900,000						9,900,000
Outstanding letters of credit	50,100,000						50,100,000
2011 Credit Agreement - 2016
Debt instrument
Debt discount	(1,542,000)						(1,542,000)
Payments Due
Maximum borrowing capacity	16,900,000						16,900,000								375,000,000
Basis spread on variable rate (as a percent)							5.50%
Commitment fee on the unused portion (as a percent)							0.50%
Outstanding borrowings	0						0
Availability for future borrowings under the revolver	2,800,000						2,800,000
Outstanding letters of credit	14,100,000						14,100,000
2011 Credit Agreement - 2016 and 2017
Payments Due
Maximum borrowing capacity	76,900,000						76,900,000
Threshold percentage for applicability of senior secured leverage ratio covenant							30.00%
Threshold amount for applicability of senior secured leverage ratio covenant	23,100,000						23,100,000
Gain (loss) on partial extinguishment of debt							(6,500,000)
Availability for future borrowings under the revolver	12,700,000						12,700,000
Term Loan A and Term Loan B
Payments Due
Gain (loss) on partial extinguishment of debt								(6,000,000)
Extinguishment of debt													$ 250,000,000