Net Income (Loss) Per Share - Anti-dilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Employee and Directors Stock Options
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive	561,457	313,028	561,457	313,787
Restricted Stock
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive		66,688		67,694
Deferred Restricted Stock
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive		29,050		29,050
Performance Shares
Antidilutive securities
Number of shares excluded as their effect would be anti-dilutive		55,762		49,432