Long-Term Debt (Narrative) (Details)		3 Months Ended				12 Months Ended
	Mar. 30, 2020 USD ($) item	Dec. 31, 2019 USD ($)	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Long-term debt, net of deferred financing costs		$ 134,001,000				$ 134,001,000	$ 135,810,000
Fixed rate debt		22,900,000				22,900,000	23,603,000
Variable rate debt		112,457,000				$ 112,457,000	115,535,000
Debt to be repaid upon sale of related properties, term						1 year
KeyBank Credit Facility [Member]
Debt Instrument [Line Items]
Weighted average interest rate						4.30%
Variable rate debt		$ 86,845,000				$ 86,845,000	89,487,000
Maturity date of debt						Oct. 31, 2020
Minimum debt yield ratio						10.00%
Fixed charge coverage ratio		1.50	1.50	1.50	1.50
Held For Use [Member]
Debt Instrument [Line Items]
Long-term debt, net of deferred financing costs		$ 135,357,000				$ 135,357,000	$ 138,000,000
Weighted average term						1 year 6 months	2 years 1 month 6 days
Weighted average interest rate						4.22%	5.15%
Fixed rate debt		22,900,000				$ 22,900,000	$ 23,604,000
Variable rate debt		$ 112,457,000				$ 112,457,000	$ 114,396,000
Fixed rate, weighted average term						2 years 3 months 18 days	1 year 10 months 24 days
Fixed rate, weighted average interest						4.41%	4.41%
Variable rate, weighted average term						1 year 2 months 12 days	2 years 10 months 24 days
Variable rate, weighted average interest						4.18%	5.30%
Subsequent Event [Member] | KeyBank Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date of debt	Apr. 01, 2021
Number of loan extensions | item	2
Minimum debt yield ratio	10.00%
Dividends or distributions permitted under loan modification	$ 0
Additional recourse debt or investments permitted under loan modification	$ 0
Subsequent Event [Member] | KeyBank Credit Facility [Member] | Extension 1 [Member]
Debt Instrument [Line Items]
Extension period	6 months
Subsequent Event [Member] | KeyBank Credit Facility [Member] | Extension 2 [Member]
Debt Instrument [Line Items]
Extension period	5 months
Minimum [Member] | KeyBank Credit Facility [Member]
Debt Instrument [Line Items]
Fixed charge coverage ratio						1.25
Minimum [Member] | Subsequent Event [Member] | KeyBank Credit Facility [Member]
Debt Instrument [Line Items]
Fixed charge coverage ratio	1.25
Maximum [Member] | KeyBank Credit Facility [Member]
Debt Instrument [Line Items]
Leverage ratio						60.00%
Fixed charge coverage ratio						1.50
Maximum [Member] | Subsequent Event [Member] | KeyBank Credit Facility [Member]
Debt Instrument [Line Items]
Leverage ratio	60.00%
Fixed charge coverage ratio	1.50