Dividend (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	May 02, 2019	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Common stock dividend
Dividend declared (in dollars per share)	$ 0.22	$ 0.22	$ 0.22	$ 0.44	$ 0.44
Dividend paid (in dollars per share)		$ 0.22	$ 0.22	$ 0.44	$ 0.44
Dividend paid (in dollars)		$ 2,753		$ 5,505	$ 5,509
Dividend deferred in accordance with Deferred Compensation Plan		$ 5		$ 12