Summary of Accounting Policies (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Allowance for credit losses	$ 1,033,000		$ 902,000
Increase (decrease) in allowance for credit losses	213,000	$ 1,187,000
Reduction in allowances from collections or adjustments	(43,000)	(10,000)
Write-offs of allowance	$ (39,000)	$ (13,000)
General Partnership
Percentage of ownership in operating partnership	99.99%		99.99%
Limited Partnership
Percentage of limited partnership interest	0.01%		0.01%