Note 4 - Real Estate (Details Textual) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended
	Jun. 30, 2021	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Operating Lease, Lease Income, Total		$ 364,694	$ 256,607		$ 929,297	$ 778,572
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, Net of Tax, Attributable to Noncontrolling Interest					3,000
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation					$ 2,200
Acquired [Member]
Operating Lease, Lease Income, Total				$ 3,200
Disposition Activity Relating to Consolidated Operating Properties and Parcels [Member]
Number of Properties Sold	2				5	3
Rite Aid Distribution Center [Member]
Prepaid Rent		$ 17,700			$ 17,700