Real Estate Real Estate (Schedule of Fixed and Variable Lease Payments) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Leases, Income Statement, Lease Revenue	$ 307,208,000	$ 294,182,000	$ 280,813,000
Amortization of Lease Incentives	(987,000)	(845,000)	(387,000)
Fixed Lease Escalation [Member]
Operating Leases, Income Statement, Lease Revenue	272,630,000	262,178,000	254,302,000
Variable Lease Escalation [Member]
Operating Leases, Income Statement, Lease Revenue	5,501,000	4,967,000	4,111,000
Straight Line Rent Income [Member]
Operating Leases, Income Statement, Lease Revenue	20,411,000	22,084,000	22,787,000
Escrow Funds Received From Tenants [Member]
Operating Leases, Income Statement, Lease Revenue	$ 9,653,000	$ 5,798,000	$ 0