Quarterly report pursuant to Section 13 or 15(d)

Share-Based Payments - Assumptions used in Estimating Fair Value (Details)

v3.7.0.1
Share-Based Payments - Assumptions used in Estimating Fair Value (Details) - All Plans - Restricted Stock
6 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected volatility (as a percent) 20.20% 20.70%
Dividend yield (as a percent) 1.10% 1.00%
Average risk-free interest rate (as a percent) 1.70% 1.70%
Average expected term (in years) 2 years 29 days 2 years 29 days