Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands		Common Stock [Member]	Preferred Stock Series C [Member]	Additional Paid-in Capital [Member]	Undistributed Income Loss [Member]	AOCI Attributable to Parent [Member]	Total
Beginning balance, value at Sep. 30, 2019		$ 964	$ 347,678	$ 662,401	$ 0		$ 1,011,043
Shares Issued in Connection with the DRIP (1)	[1]	19	0	25,281	0		25,300
Shares Issued in Connection with At-The-Market Offerings of 6.125% Series C Preferred Stock, net of offering costs		0	86,172	(1,357)	0		84,815
Shares Repurchased through the Common Stock Repurchase Plan		(4)	0	(4,272)	0		(4,276)
Shares Issued Through the Exercise of Stock Options		1	0	1,015	0		1,016
Stock Compensation Expense		0	0	368	0		368
Distributions To Common Shareholders		0	0	(94,481)	44,700		(49,781)
Net Loss Attributable to Shareholders		0	0	0	(25,231)		(25,231)
Preferred Dividends		0	0	0	(19,469)		(19,469)
Ending balance, value at Jun. 30, 2020		980	433,850	588,955	0		1,023,785
Beginning balance, value at Mar. 31, 2020		980	429,215	578,648	0		1,008,843
Shares Issued in Connection with the DRIP (1)	[1]	1	(0)	1,171	0		1,172
Shares Issued in Connection with At-The-Market Offerings of 6.125% Series C Preferred Stock, net of offering costs		0	4,635	(107)	0		4,528
Shares Repurchased through the Common Stock Repurchase Plan		(1)	0	(1,065)	0		(1,066)
Stock Compensation Expense		0	0	98	0		98
Distributions To Common Shareholders		0	0	10,210	(26,851)		(16,641)
Net Loss Attributable to Shareholders		0	0	0	33,458		33,458
Preferred Dividends		0	0	0	(6,607)		(6,607)
Ending balance, value at Jun. 30, 2020		980	433,850	588,955	0		1,023,785
Beginning balance, value at Sep. 30, 2020		981	471,994	568,998	0	$ (4,368)	1,037,605
Shares Issued in Connection with the DRIP (1)	[1]	1	0	1,354	0	0	1,355
Shares Issued in Connection with At-The-Market Offerings of 6.125% Series C Preferred Stock, net of offering costs		0	77,646	(1,688)	0	0	75,958
Shares Issued Through the Exercise of Stock Options		1	0	1,965	0	0	1,966
Stock Compensation Expense		0	0	210	0	0	210
Distributions To Common Shareholders		0	0	16,891	(68,950)	0	(52,059)
Net Loss Attributable to Shareholders		0	0	0	93,953	0	93,953
Preferred Dividends		0	0	0	(25,003)	0	(25,003)
Change in Fair Value of Interest Rate Swap Agreement		0	0	0	0	1,862	1,862
Ending balance, value at Jun. 30, 2021		983	549,640	587,730	0	(2,506)	1,135,847
Beginning balance, value at Mar. 31, 2021		983	549,640	588,049		(2,572)	1,136,100
Shares Issued in Connection with the DRIP (1)	[1]	0	0	7	0	0	7
Stock Compensation Expense		0	0	77	0	0	77
Distributions To Common Shareholders		0	0	(403)	(17,292)	0	(17,695)
Net Loss Attributable to Shareholders		0	0	0	25,708	0	25,708
Preferred Dividends		0	0	0	(8,416)	0	(8,416)
Change in Fair Value of Interest Rate Swap Agreement		0	0	0	0	66	66
Ending balance, value at Jun. 30, 2021		$ 983	$ 549,640	$ 587,730	$ 0	$ (2,506)	$ 1,135,847

[1] Dividend Reinvestment and Stock Purchase Plan