Stock-Based Compensation - Restricted Stock (Details) - Restricted stock	12 Months Ended
	Sep. 30, 2021 $ / shares shares
Weighted Average Price
Nonvested shares, weighted average grant date fair value at beginning period (in dollars per share) | $ / shares	$ 22.27
Granted (in dollars per share) | $ / shares	28.88
Vested (in dollars per share) | $ / shares	21.22
Forfeited (in dollars per share) | $ / shares	23.72
Nonvested shares, weighted average grant date fair value at ending period (in dollars per share) | $ / shares	$ 26.01
Restricted Shares/Units
Nonvested shares at beginning period (in shares) | shares	1,334,839
Granted (in shares) | shares	548,458
Vested (in shares) | shares	(697,026)
Forfeited (in shares) | shares	(37,383)
Nonvested shares at ending period (in shares) | shares	1,148,888