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Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Debt (Narrative) (Details) (USD $)	0 Months Ended	3 Months Ended	6 Months Ended				0 Months Ended	6 Months Ended							3 Months Ended		6 Months Ended		0 Months Ended		6 Months Ended			6 Months Ended
Debt (Narrative) (Details) (USD $)	Jun. 14, 2011	Jun. 30, 2011	Dec. 31, 2019	Jun. 30, 2011	Jul. 31, 2011	Dec. 31, 2010	Jul. 14, 2011 Repayment of Debt [Member] 9.125% Senior Notes Due April 1, 2018 [Member]	Jun. 30, 2011 June 15, 2015 through June 14, 2016 [Member] 7.00% Senior Notes Due June 15, 2019 [Member]	Jun. 30, 2011 June 15, 2016 through June 14, 2017 [Member] 7.00% Senior Notes Due June 15, 2019 [Member]	Jun. 30, 2011 June 15, 2016 through June 14, 2017 [Member] 7.25% Senior Notes Due 2021 [Member]	Jun. 30, 2011 June 15, 2017 and beyond [Member] 7.00% Senior Notes Due June 15, 2019 [Member]	Jun. 30, 2011 June 15, 2017 and beyond [Member] 7.25% Senior Notes Due 2021 [Member]	Jun. 30, 2011 June 15, 2017 through June 14, 2018 [Member] 7.25% Senior Notes Due 2021 [Member]	Jun. 30, 2011 June 15, 2018 through June 14, 2019 [Member] 7.25% Senior Notes Due 2021 [Member]	Jun. 30, 2011 7.00% Senior Notes Due June 15, 2019 [Member]	Jun. 30, 2011 7.25% Senior Notes Due 2021 [Member]	Jun. 30, 2011 Prior To June 15, 2014 [Member]	Jun. 30, 2011 Revolving Credit Facility [Member]	Jul. 14, 2011 9.125% Senior Notes Due April 1, 2018 [Member]	Jun. 30, 2011 9.125% Senior Notes Due April 1, 2018 [Member]	Jun. 30, 2011 4.00% Convertible Senior Notes Due April 1, 2017 [Member]	Jun. 30, 2011 9.00% Convertible Senior Notes Due August 1, 2012 [Member]	Jun. 30, 2011 Senior Notes [Member]	Jun. 30, 2011 ICG Debt [Member]
Percentage of maximum redemption aggregate principal amount from equity proceeds																	35.00%
Call premium								103.50%	101.75%	103.625%	100.00%	100.00%	102.417%	101.208%
Tender offer price upon change in control			101.00%
Incurred financing fees																		$ 20,700,000					$ 44,200,000
Calculated conversion rate																					2,614.6848	2,392.73414
Principal amount increment for conversion																					1,000	1,000
Registration statement effective date deadline															June 13, 2012	June, 13 2012
Registration Rights agreement violation per annum penalty in first 90 days															0.25%	0.25%
Registration rights agreement violation additional per annum penalty															0.25%	0.25%
Registration Rights agreement violation maximum per annum penalty															1.00%	1.00%
Restricted cash		350,966,000		350,966,000																260,700,000
Subsequent event, senior notes redeemed							251,400,000
Accrued interest																			5,200,000
Debt conversion converted instrument amount					4,500,000
Debt assumed in acquisition		604,800,000		604,800,000																	298,500,000	1,700,000		54,000,000
Remaining balance of other ICG debt		10,264,000		10,264,000		14,093,000																		5,200,000
Net loss resulting from early retirement of ICG debt		(250,000)		(250,000)																				300,000
Revolving credit facility borrowings outstanding		360,000,000		360,000,000
Line of credit facility maturity term	5
Line of credit facility, expiration date	June 14, 2016
Line of credit facility, unused capacity, commitment fee percentage				0.50%
Secured revolving credit facility maximum borrowing amount	2,000,000,000
Line of credit facility, remaining borrowing capacity		1,100,000,000		1,100,000,000
Letters of credit outstanding, amount		$ 76,200,000		$ 76,200,000