Earnings Per Share - Basic (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2020	Jun. 30, 2019
Net Income (Loss) Attributable to Parent [Abstract]
Net income attributable to common shareholders	$ 15,747	$ 1,537	$ 5,461	$ 17,202	$ 4,212	$ 5,154	$ 22,745	$ 26,568
Earnings Per Share, Basic [Abstract]
Weighted average number of basic common shares outstanding (in shares)	51,489,211			51,414,619			51,489,211	51,414,619
Net income per common share attributable to common shareholders, basic (in dollars per share)	$ 0.31			$ 0.33			$ 0.44	$ 0.52