Stock and Other Compensation Plans - Narrative (Details) - USD ($) shares in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based compensation cost	$ 33,200,000	$ 25,400,000	$ 23,700,000
Capitalized stock-based compensation cost	$ 20,500,000	14,700,000	13,500,000
Maximum shares authorized (in shares)	13.2
Shares available for future issuance (in shares)	2.2
Service period	3 years
Unrecognized compensation cost	$ 21,600,000
Cost recognition period	1 year 3 months 18 days
Fair value of restricted stock vested	$ 24,000,000.0	$ 21,600,000	$ 22,800,000
Minimum initial investment	1,250
Minimum cash payments	25
Maximum annual cash payments	$ 100,000