Real Estate (Key Information for Leases) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) tenant	Dec. 31, 2020 USD ($)
Lessor, Lease, Description [Line Items]
Weighted average remaining lease term	10 years 7 months 6 days
Leases classified as operating leases | tenant	3,150
Leases classified as direct financing leases | tenant	6
Rent deferral, year ending December 31, 2021		$ 51,269
Rent deferral, year ending December 31, 2020	$ 4,677
Deferred rent repaid	10,817	$ 3,259
Deferred rent to be repaid during year ended December 31, 2021	$ 21,107
Minimum
Lessor, Lease, Description [Line Items]
Initial lease term	10 years
Maximum
Lessor, Lease, Description [Line Items]
Initial lease term	20 years