Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020
Common Stock Class A Non-voting
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	52,873,568	52,332,848	52,097,590
Common stock, shares outstanding (in shares)	52,873,568	52,332,848	52,097,590
Common Stock Class B Voting
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	3,000,000	3,000,000	3,000,000
Common stock, shares issued (in shares)	2,970,171	2,970,171	2,970,171
Common stock, shares outstanding (in shares)	2,970,171	2,970,171	2,970,171