Share-Based Compensation - Restricted Stock Plan (Details) $ in Millions	12 Months Ended
	Sep. 30, 2021 USD ($) shares
Share-based Payment Arrangement [Abstract]
Share-based compensation arrangement by share-based payment award, shares issued in period (in shares)	1,500,000
Share-based compensation arrangement by share-based payment award, non-option equity instruments, granted (in shares)	600,000
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized | $	$ 21.3
Employee service share-based compensation, nonvested awards, total compensation cost not yet recognized, period for recognition - restricted stock	1 year 3 months 3 days