Net Income (Loss) Per Share - Anti-dilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee and Directors Stock Options
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive	299,093	446,182	263,376	352,358
Restricted Stock
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive	81,380	61,688	82,105	65,692
Deferred Restricted Stock
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive	36,499	29,050	35,547	29,050
Performance Shares
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive	46,581	51,120	46,581	49,994