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Debt (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended									9 Months Ended		9 Months Ended			0 Months Ended		2 Months Ended	9 Months Ended		2 Months Ended	9 Months Ended		9 Months Ended	3 Months Ended	9 Months Ended
Debt (Narrative) (Details) (USD $)	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Jul. 14, 2011 Repayment of Debt [Member] 9.125% Senior Notes Due April 1, 2018 [Member]	Sep. 30, 2011 June 15, 2015 through June 14, 2016 [Member] 7.00% Senior Notes Due June 15, 2019 [Member]	Sep. 30, 2011 June 15, 2016 through June 14, 2017 [Member] 7.00% Senior Notes Due June 15, 2019 [Member]	Sep. 30, 2011 June 15, 2016 through June 14, 2017 [Member] 7.25% Senior Notes Due 2021 [Member]	Sep. 30, 2011 June 15, 2017 and beyond [Member] 7.00% Senior Notes Due June 15, 2019 [Member]	Sep. 30, 2011 June 15, 2017 and beyond [Member] 7.25% Senior Notes Due 2021 [Member]	Sep. 30, 2011 June 15, 2017 through June 14, 2018 [Member] 7.25% Senior Notes Due 2021 [Member]	Sep. 30, 2011 June 15, 2018 through June 14, 2019 [Member] 7.25% Senior Notes Due 2021 [Member]	Sep. 30, 2011 7.00% Senior Notes Due June 15, 2019 [Member]	Jun. 30, 2011 7.00% Senior Notes Due June 15, 2019 [Member]	Sep. 30, 2011 7.25% Senior Notes Due 2021 [Member]	Jun. 30, 2011 7.25% Senior Notes Due 2021 [Member]	Sep. 30, 2011 Prior To June 15, 2014 [Member]	Sep. 30, 2011 Revolving Credit Facility [Member]	Sep. 30, 2011 Accounts Securitization Program [Member]	Jul. 14, 2011 9.125% Senior Notes Due April 1, 2018 [Member]	Jun. 14, 2011 9.125% Senior Notes Due April 1, 2018 [Member]	Aug. 15, 2011 4.00% Convertible Senior Notes Due April 1, 2017 [Member]	Sep. 30, 2011 4.00% Convertible Senior Notes Due April 1, 2017 [Member]	Jun. 14, 2011 4.00% Convertible Senior Notes Due April 1, 2017 [Member]	Aug. 15, 2011 9.00% Convertible Senior Notes Due August 1, 2012 [Member]	Sep. 30, 2011 9.00% Convertible Senior Notes Due August 1, 2012 [Member]	Jun. 14, 2011 9.00% Convertible Senior Notes Due August 1, 2012 [Member]	Sep. 30, 2011 Senior Notes [Member]	Sep. 30, 2011 ICG Debt [Member]	Sep. 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	21,428,000		21,428,000																		260,700,000
Subsequent event, senior notes redeemed					251,400,000
Accrued interest																				5,200,000
Debt Instrument, Convertible, Latest Date																							August 17, 2011			August 17, 2011
Debt assumed in acquisition	604,800,000		604,800,000																					298,500,000			1,700,000		54,000,000	54,000,000
Net loss resulting from early retirement of debt	1,708,000	6,776,000	1,958,000	6,776,000																									(1,700,000)	(2,000,000)
Line of credit borrowings outstanding																		300,000,000	40,000,000
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		2,000,000,000
Line of credit facility, remaining borrowing capacity	1,000,000,000		1,000,000,000
Letters of credit outstanding, amount	$ 141,000,000		$ 141,000,000