XML 104 R88.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-based Compensation Plans (Schedule of Share-based Compensation, Phantom Award Activity) (Details) - Phantom Share Units (PSUs) [Member] - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Outstanding, shares 534,026 558,878 643,288  
Outstanding, Weighted average grant date fair value per share $ 11.36 $ 9.60 $ 8.49 $ 6.22
Outstanding, Weighted average remaining contractual term 11 months 11 months 9 months 7 days 9 months 7 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 199,260 302,875 289,524  
Granted, Weighted average grant date fair value per share $ 13.22 $ 9.84 $ 9.78  
Vested, shares (278,000) (270,822) (317,409)  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value $ 3.7 $ 2.5 $ 3.1  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (103,279) (56,905) (56,525)  
Canceled, Weighted average grant date fair value per share $ 10.87 $ 9.28 $ 8.29  
Outstanding, shares 352,007 534,026 558,878 643,288