Accounts Receivable, Net (Schedule Of Accounts Receivable) (Details) $ in Thousands	Oct. 01, 2017 properties	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Insurance Settlements Receivable		$ 27	$ 1,967
Revenue Bond Receivable		10,808	22,164
Straight-line rent receivable		73,657	67,618
Allowance for doubtful accounts		(1,384)	(871)
Total		99,213	98,939
number of leases terminated | properties	9
Tenants [Member]
Carrying amounts of accounts receivable		15,977	7,564
Non-Tenants [Member]
Carrying amounts of accounts receivable		128	$ 497
early childhood education center [Member]
Straight-line rent receivable		9,000
early childhood education center [Member] | Tenants [Member]
Carrying amounts of accounts receivable		5,400
Total		$ 64
completed early childhood education properties [Member]
number of leases terminated | properties	7
unimproved land [Member]
number of leases terminated | properties	2