Note 6 - Impairments - Asset Impairment Charges (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gross property impairment charges		$ 3,597	$ 6,624	$ 48,743
Total net impairment charges		3,600	6,600	48,700
Properties Marketed for Sale [Member]
Gross property impairment charges	[1]	2,700	5,500	12,500
Disposed Operating Properties [Member]
Gross property impairment charges	[2]	0	1,100	36,200
Cost Method Investment [Member]
Gross property impairment charges	[3]	$ 900	$ 0	$ 0

[1] Amounts relate to adjustments to property carrying values for properties which the Company has marketed for sale as part of its capital recycling program and as such has adjusted the anticipated hold periods for such properties.

[2] Amounts relate to dispositions/deeds in lieu/foreclosures during the respective years shown.

[3] Amounts relate to a cost method investment during the respective years shown.