Leases (Components of Lease Income) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating Lease Income [Line Items]
Sales-type and Direct Financing Leases, Lease Income		$ 6,437	$ 6,092	$ 19,099	$ 17,988
Operating Lease, Lease Income	[1]	2,270	1,984	6,491	5,816
Lease Income		8,707	8,076	25,590	23,804
Operating Lease Income from Related Party [Member]
Operating Lease Income [Line Items]
Operating Lease, Lease Income		$ 19	$ 19	$ 57	$ 56

[1] (a) Includes rent from Tower Properties Company, a related party, of $19 thousand for the three month periods ended September 30, 2020 and 2019, and $57 thousand and $56 thousand, respectively, for the nine months ended September 30, 2020 and 2019.