Dividend (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				9 Months Ended
	Jul. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Common stock dividend
Dividend declared (in dollars per share)	$ 0.22	$ 0.22			$ 0.22	$ 0.66	$ 0.66
Dividend paid (in dollars per share)		$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.66	$ 0.66
Dividend paid (in dollars)		$ 2,762	$ 2,763	$ 2,760		$ 8,285	$ 8,258
Dividend deferred in accordance with Deferred Compensation Plan		$ 30	$ 18	$ 77