Debt and Derivative Instruments (Schedule of Mortgages and Credit Facility Payable) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Mortgage Loans On Real Estate [Line Items]
Mortgages payable	$ 317,943	$ 416,017
Credit facility payable	279,000	215,000
Total debt before unamortized mortgage premiums and debt issuance costs including impact of interest rate swaps	596,943	631,017
Add: Unamortized mortgage premiums	17	419
Less: Unamortized debt issuance costs	(1,418)	(2,718)
Total debt	$ 595,542	$ 628,718
Mortgages Payable, Weighted Average Interest Rate	3.59%	3.69%
Credit Facilities Payable, Weighted Average Interest Rate	3.03%	3.89%
Total debt before unamortized mortgage premiums and debt issuance costs including impact of interest rate swaps, Weighted Average Interest Rate	3.33%	3.76%
Fixed rate mortgages payable [Member]
Mortgage Loans On Real Estate [Line Items]
Mortgages payable	$ 118,463	$ 163,738
Mortgages Payable, Weighted Average Interest Rate	3.88%	4.25%
Variable rate mortgages payable with swap agreements [Member]
Mortgage Loans On Real Estate [Line Items]
Mortgages payable	$ 198,796	$ 251,595
Mortgages Payable, Weighted Average Interest Rate	3.42%	3.33%
Variable rate mortgages payable [Member]
Mortgage Loans On Real Estate [Line Items]
Mortgages payable	$ 684	$ 684
Mortgages Payable, Weighted Average Interest Rate	1.70%	1.75%