Stock-Based Compensation Plans - Summary of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Options outstanding	251,845	189,015
Options granted	68,865
Options forfeited	(6,035)
Options outstanding weighted average exercise price	$ 20.59	$ 21.49
Options outstanding weighted average exercise price - Granted	18.40
Options outstanding weighted average exercise price - forfeited	$ 23.99
Options outstanding weighted average remaining term	7 years 3 months 16 days	6 years 3 months 18 days
Options outstanding weighted average grant date fair value	$ 1,749	$ 1,531
Options granted weighted average grant date fair value	$ 275
Options forfeited weighted average grant date fair value	$ (57)
Options exercisable	122,494
Options exerciseable weighted average exercise price	$ 22.08
Options exercisable weighted average remaining term	5 years 6 months
Options exerciseable weighted average grant date fair value	$ 1,002
Options vested	24,445
Options vested weighted average grant date fair value	$ 204