CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Shares	Paid-in Capital	Accumulated Distributions in Excess of Earnings	Total Beneficial Interest	Noncontrolling Interest in Operating Partnership	Noncontrolling Interest in Partially Owned Properties	Accumulated Other Comprehensive Income (Loss)	Total
Beginning Balance at Dec. 31, 2018		$ 122,624	$ (24,741)	$ 97,883	$ 183,360	$ 2,538	$ (30)	$ 283,751
Beginning Balance (in shares) at Dec. 31, 2018	8,967,000
Shares/units redeemed		(197)		(197)	(629)			(826)
Shares/units redeemed (in shares)	(11,000)
Dividends declared			(2,374)	(2,374)	(4,661)			(7,035)
Dividends reinvested - stock dividend		1,479		1,479				1,479
Dividends reinvested - stock dividend (in shares)	82,000
Issuance of shares under optional purchase plan		929		929				929
Issuance of shares under optional purchase plan (in shares)	49,000
Change in fair value of interest rate swaps							4	4
Net income			1,288	1,288	2,532	(30)		3,790
Ending balance at Mar. 31, 2019		124,835	(25,827)	99,008	180,602	2,508	(26)	282,092
Ending balance (in shares) at Mar. 31, 2019	9,087,000
Beginning Balance at Dec. 31, 2018		122,624	(24,741)	97,883	183,360	2,538	(30)	283,751
Beginning Balance (in shares) at Dec. 31, 2018	8,967,000
Dividends reinvested - stock dividend								$ 3,033
Dividends reinvested - stock dividend (in shares)								168,000
Change in fair value of interest rate swaps								$ 7
Net income								8,611
Ending balance at Jun. 30, 2019		127,030	(26,585)	100,445	178,863	2,491	(23)	281,776
Ending balance (in shares) at Jun. 30, 2019	9,206,000
Beginning Balance at Mar. 31, 2019		124,835	(25,827)	99,008	180,602	2,508	(26)	282,092
Beginning Balance (in shares) at Mar. 31, 2019	9,087,000
Shares/units redeemed		(154)		(154)	(273)			(427)
Shares/units redeemed (in shares)	(9,000)
Dividends declared			(2,405)	(2,405)	(4,657)			(7,062)
Dividends reinvested - stock dividend		1,554		1,554				1,554
Dividends reinvested - stock dividend (in shares)	86,000
Issuance of shares under optional purchase plan		795		795				795
Issuance of shares under optional purchase plan (in shares)	42,000
Change in fair value of interest rate swaps							3	3
Net income			1,647	1,647	3,191	(17)		4,821
Ending balance at Jun. 30, 2019		127,030	(26,585)	100,445	178,863	2,491	(23)	281,776
Ending balance (in shares) at Jun. 30, 2019	9,206,000
Beginning Balance at Dec. 31, 2019		131,261	(28,888)	102,373	174,221	2,416	37	$ 279,047
Beginning Balance (in shares) at Dec. 31, 2019	9,436,000							9,436,000
Contribution of assets in exchange for the issuance of noncontrolling interest shares					9,031			$ 9,031
Shares/units redeemed		(696)		(696)	(541)			(1,237)
Shares/units redeemed (in shares)	(38,000)
Dividends declared			(2,527)	(2,527)	(4,831)			(7,358)
Dividends reinvested - stock dividend		1,584		1,584				1,584
Dividends reinvested - stock dividend (in shares)	87,000
Issuance of shares under optional purchase plan		1,203		1,203				1,203
Issuance of shares under optional purchase plan (in shares)	62,000
Change in fair value of interest rate swaps							(1,486)	(1,486)
Net income			1,813	1,813	3,419	(5)		5,227
Ending balance at Mar. 31, 2020		133,352	(29,602)	103,750	181,299	2,411	(1,449)	286,011
Ending balance (in shares) at Mar. 31, 2020	9,547,000
Beginning Balance at Dec. 31, 2019		131,261	(28,888)	102,373	174,221	2,416	37	$ 279,047
Beginning Balance (in shares) at Dec. 31, 2019	9,436,000							9,436,000
Dividends reinvested - stock dividend								$ 3,192
Dividends reinvested - stock dividend (in shares)								175,000
Change in fair value of interest rate swaps								$ (2,108)
Net income								11,624
Ending balance at Jun. 30, 2020		134,532	(29,944)	104,588	180,439	2,429	(2,071)	$ 285,385
Ending balance (in shares) at Jun. 30, 2020	9,610,000							9,610,000
Beginning Balance at Mar. 31, 2020		133,352	(29,602)	103,750	181,299	2,411	(1,449)	$ 286,011
Beginning Balance (in shares) at Mar. 31, 2020	9,547,000
Shares/units redeemed		(1,039)		(1,039)	(209)			(1,248)
Shares/units redeemed (in shares)	(57,000)
Dividends declared			(2,544)	(2,544)	(4,828)			(7,372)
Dividends reinvested - stock dividend		1,608		1,608				1,608
Dividends reinvested - stock dividend (in shares)	88,000
Issuance of shares under optional purchase plan		611		611				611
Issuance of shares under optional purchase plan (in shares)	32,000
Change in fair value of interest rate swaps							(622)	(622)
Net income			2,202	2,202	4,177	18		6,397
Ending balance at Jun. 30, 2020		$ 134,532	$ (29,944)	$ 104,588	$ 180,439	$ 2,429	$ (2,071)	$ 285,385
Ending balance (in shares) at Jun. 30, 2020	9,610,000							9,610,000