Dividend (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 03, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
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
Dividend paid (in dollars)		$ 2,752		$ 8,257	$ 8,240