Share-Based Payments - Stock Option Awards (Details) - Stock Option Awards - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Stock Options, Number of Outstanding Options
Outstanding at the beginning of the period (in shares)	5,316
Granted (in shares)	1,486	1,200	1,600
Exercised (in shares)	(938)
Forfeited or expired (in shares)	(280)
Outstanding at the end of the period (in shares)	5,584	5,316
Exercisable at the end of the period (in shares)	3,550
Stock Options, Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 21.89
Granted (in dollars per share)	23.65
Exercised (in dollars per share)	17.27
Forfeited or expired (in dollars per share)	25.64
Outstanding at the end of the period (in dollars per share)	22.95	$ 21.89
Exercisable at the end of the period (in dollars per share)	$ 21.54
Stock Options, Weighted Average Remaining Contractual Term
Weighted average remaining contractual term (in years)	6 years 1 month 6 days	6 years 9 months 18 days
Exercisable at the end of the period	5 years 4 months 24 days
Stock Options, Aggregate Intrinsic Value
Outstanding at the beginning of the period (in dollars)	$ 19,255
Outstanding at the end of the period (in dollars)	19,615	$ 19,255
Exercisable at the end of the period (in dollars)	$ 17,071
Minimum
Share-Based Payments
Vesting period	3 years
Maximum
Share-Based Payments
Term of stock options	10 years
Vesting period	4 years