Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013	Jan. 03, 2015	Aug. 14, 2014	Aug. 04, 2014
Class of Stock [Line Items]
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Common stock, shares authorized	500,000,000	500,000,000	500,000,000
Stock authorized to repurchase	$ 100,000		$ 100,000	$ 100,000			$ 600,000
Accelerated Share Repurchases, Settlement (Payment) or Receipt						$ 125,000
Repurchases of common stock, shares		2,728,000	5,068,000	3,053,000
Stock repurchased in the period , including holdback			$ 224,915
Repurchases of common stock, value		$ 64,940	$ 187,415	$ 74,871
Series A Junior Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized		500,000
Accelerated Share Repurchases, Date [Domain]
Class of Stock [Line Items]
Repurchases of common stock, shares	2,300,000
Shares that would be deliverable upon settlement of accelerated share repurchase plan					1,070,307
Common Stock [Member]
Class of Stock [Line Items]
Repurchases of common stock, shares		2,728,000	5,068,000	3,053,000
Repurchases of common stock, value		$ 27	$ 51	$ 31
Additional Paid-in Capital [Member]
Class of Stock [Line Items]
Repurchases of common stock, value		$ 64,913	187,364	$ 74,840
Accelerated Share Repurchases, Date [Domain] | Accelerated Share Repurchases, Date [Domain]
Class of Stock [Line Items]
Repurchases of common stock, value			$ 37,500