Stockholders' Equity (Details) (USD $)	0 Months Ended	12 Months Ended					12 Months Ended	0 Months Ended	12 Months Ended			0 Months Ended	12 Months Ended
	Aug. 04, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Aug. 04, 2014	Sep. 30, 2014 Series A Junior Participating Preferred Stock [Member]	Sep. 30, 2014 Accelerated Share Repurchases, Date [Domain]	Aug. 14, 2014 Common Stock [Member]	Sep. 30, 2014 Common Stock [Member]	Sep. 30, 2013 Common Stock [Member]	Sep. 30, 2012 Common Stock [Member]	Aug. 14, 2014 Additional Paid-in Capital [Member]	Sep. 30, 2014 Additional Paid-in Capital [Member]	Sep. 30, 2013 Additional Paid-in Capital [Member]	Sep. 30, 2012 Additional Paid-in Capital [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		5,000,000	5,000,000			500,000
Common stock, shares authorized		500,000,000	500,000,000
Stock authorized to repurchase	$ 600,000,000	$ 100,000,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt					125,000,000
Common stock repurchase holdback		187,415,000						23,000				87,500,000	37,500,000
Repurchases of common stock, shares		5,068,000	3,053,000	1,553,000			2,300,000		5,068,000	3,053,000	1,553,000
Percentage of initial shares to total fixed purchase price		70.00%
Maximum shares that could be issued under Accelerated Share Repurchase program		25,000,000
Maximum % of shares that could be issued under Accelerated Share Repurchase Plan		20.00%
Repurchases of common stock, value		$ 224,915,000	$ 74,871,000	$ 34,953,000					$ 51,000	$ 31,000	$ 15,000		$ 187,364,000	$ 74,840,000	$ 34,938,000
Shares that would be deliverable upon settlement of accelerated share repurchase plan		982,419