Net Income (Loss) Per Share - Computation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator: Basic and Diluted
Net income (loss) - Basic	$ 713	$ (3,967)	$ (23,881)	$ (6,529)
Net income (loss) - Diluted	713	(3,967)	(23,881)	(6,529)
Dividends paid and accrued	(2,756)	(2,752)	(8,272)	(8,257)
Undistributed income (loss) - Basic	(2,043)	(6,719)	(32,153)	(14,786)
Undistributed income (loss) - Diluted	$ (2,043)	$ (6,719)	$ (32,153)	$ (14,786)
Percentage allocated to common shares	100.00%	100.00%	100.00%	100.00%
Undistributed income (loss) allocated to common shares - Basic	$ (2,043)	$ (6,719)	$ (32,153)	$ (14,786)
Undistributed income (loss) allocated to common shares - Diluted	(2,043)	(6,719)	(32,153)	(14,786)
Dividends paid on common shares outstanding	2,731	2,725	8,196	8,176
Net income (loss) available to common shares - Basic	688	(3,994)	(23,957)	(6,610)
Net income (loss) available to common shares - Diluted	$ 688	$ (3,994)	$ (23,957)	$ (6,610)
Denominator: Basic and Diluted
Weighted average common shares outstanding - Basic	12,422,485	12,400,522	12,418,579	12,394,350
Adjustment for dilutive potential common shares	7,144
Weighted average shares outstanding - Diluted	12,429,629	12,400,522	12,418,579	12,394,350
Basic net income (loss) per share (in dollars per share)	$ 0.06	$ (0.32)	$ (1.93)	$ (0.53)
Diluted net income (loss) per share (in dollars per share)	$ 0.06	$ (0.32)	$ (1.93)	$ (0.53)