Note 6 - Impairments - Asset Impairment Charges (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Asset Impairment Charges, Total		$ 48,743	$ 79,207	$ 67,331
Total net impairment charges*	[1]	48,700	79,200	67,300
Properties Marketed for Sale [Member]
Asset Impairment Charges, Total	[2],[3]	12,500	59,500	34,000
Disposed Operating Properties [Member]
Asset Impairment Charges, Total	[4]	36,200	19,700	17,100
Properties Held and Used [Member]
Asset Impairment Charges, Total	[5]	$ 0	$ 0	$ 16,200

[1] See Footnote 15 of the Notes to Consolidated Financial Statements for additional disclosure on fair value.

[2] During December 2018, the Company recognized an impairment charge of $41.0 million related to a development project located in Jacksonville, FL, for which the Company no longer intends to develop. The Company is marketing the property as is for sale.

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

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

[5] During 2017, the Company recognized an impairment charge of $16.2 million related to a property for which the Company had re-evaluated its long-term plan for the property due to unfavorable local market conditions.