Share-Based Payments (Narrative) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for issuance (in shares)	17,900,000
Shares available for future awards (in shares)	2,400,000
Share-based compensation expense	$ 24,500,000	$ 26,500,000	$ 27,500,000
Tax benefit recognized for share-based compensation arrangements	$ 5,800,000	$ 6,300,000	$ 6,600,000
Share options granted (in shares)	0
Share options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Expiration period (in years)	10 years
Share options granted (in shares)		100,000
Compensation expense to be recognized over vesting period	$ 2,100,000
Unrecognized compensation expense, share options	$ 800,000
Unrecognized compensation expense, weighted-average period to recognize (in years)	1 year 8 months 12 days
PSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, weighted-average period to recognize (in years)	1 year 3 months 18 days
Unrecognized compensation expense, RSE awards	$ 11,400,000
Weighted-average grant date fair value, granted (in usd per share)	$ 46.84	$ 45.96	$ 58.55
Estimated fair value of vested awards	$ 7.7
RSE awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, weighted-average period to recognize (in years)	1 year 2 months 12 days
Unrecognized compensation expense, RSE awards	$ 21,500,000
Weighted-average grant date fair value, granted (in usd per share)	$ 35.56	$ 34.54	$ 40.17
Estimated fair value of vested awards	$ 16,800,000	$ 15,600,000	$ 20,200,000