Earnings per Share - EPS Reconciliation (Details) - USD ($)	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income	$ 16,300,000.0	$ 18,200,000.0
Less: Net income allocated to participating securities	(300,000)	(300,000)
Net income allocated to common shareholders	$ 16,000,000	$ 17,900,000
Weighted average number of common shares outstanding	18,750,270	18,659,748
Dilutive potential common shares outstanding:
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	324,292	333,298
Diluted weighted-average shares	19,074,562	18,993,046