Earnings Per Share (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock			$ 71,751	$ 125,541	$ 158,762
Goldman Sachs Accelerated Share Repurchase Program [Member]
Accelerated Share Repurchases [Line Items]
Accelerated Share Repurchase Program, Execution Date					Jun. 02, 2015
Accelerated Share Repurchase Program, Completion Date					Sep. 03, 2015
Accelerated Share Repurchases, Final Price Paid Per Share					$ 49.89
Payments for Repurchase of Common Stock					$ 125,000
Purchases of treasury stock, shares	458	2,048			2,506