Stockholders' Equity (Details) (USD $)	0 Months Ended			12 Months Ended																				3 Months Ended			0 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 17, 2012	May 11, 2010	Jan. 12, 2010	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 Minimum	Mar. 31, 2012 Minimum	Sep. 30, 2010 Minimum	Sep. 30, 2012 Maximum	Sep. 30, 2010 Maximum	Sep. 30, 2012 Senior Notes	Sep. 30, 2011 Senior Notes	Sep. 30, 2012 Convertible Subordinated Debt	Sep. 30, 2011 Convertible Subordinated Debt	Sep. 30, 2012 Tangible Equity Units Senior Notes TEUs	Jul. 17, 2012 Tangible Equity Units Senior Notes TEUs	Mar. 31, 2012 Tangible Equity Units Senior Notes TEUs	Sep. 30, 2010 Tangible Equity Units Senior Notes	May 31, 2010 Tangible Equity Units Senior Notes TEUs	May 11, 2010 Tangible Equity Units Senior Notes TEUs	Sep. 30, 2012 TEU Senior Amortizing Notes Maturing August 2013 [Member] Senior Notes	Sep. 30, 2011 TEU Senior Amortizing Notes Maturing August 2013 [Member] Senior Notes	Mar. 31, 2012 7 1/2% Mandatory Convertible Subordinated Notes [Member] Convertible Subordinated Debt	Sep. 30, 2012 7 1/2% Mandatory Convertible Subordinated Notes [Member] Convertible Subordinated Debt	Oct. 11, 2012 Repurchase of Equity	Jul. 17, 2012 Common Stock	May 11, 2010 Common Stock	Jan. 12, 2010 Common Stock	Mar. 31, 2012 Common Stock	Mar. 31, 2012 Common Stock	Sep. 30, 2012 Common Stock	Sep. 30, 2010 Common Stock
Class of Stock [Line Items]
Authorized number of shares				100,000,000	180,000,000																					100,000,000
Shares of common stock exchanged for the 2010 TEUs																														2,800,000		4,969,000
Tangible Equity Units (TEUs) issued during period (units)																200,000	4,600,000	2,800,000		3,000,000	3,000,000
Percentage of original issuance of 2010 TEUs that were exchanged								94.00%
Amortizing notes outstanding																						$ 316,000	$ 10,062,000
Number of common stock exchanged for debt (shares)																															2,200,000
Value of convertible debt exchanged for common stock																								48,100,000
Long-term debt				1,498,198,000	1,488,826,000							1,201,067,000	1,132,152,000	9,402,000	57,500,000										9,400,000
Number of shares in underwritten public offering (shares)																											4,400,000	2,500,000	4,485,000			4,400,000	6,985,000
Proceeds from issuance of TEU prepaid stock purchase contracts	171,400,000	141,600,000	97,800,000	88,361,000		57,429,000
Prepaid stock purchase contract settlement factor							1.40746		0.70252	1.72414	0.86058
Prepaid Stock Contract, Fair Value																			57,400,000
Initial fair value of prepaid stock purchase contracts																88,400,000
Treasury stock utilized in public offering of stock (shares)			700,000
Number of shares surrendered by emloyees (shares)				9,156	10,440	6,589
Aggregate value of stock surrendered				$ 126,000	$ 170,000	$ 160,000