Note 12 - Fair Value Measurements - Estimate of Fair Value Differs From Carrying Amounts (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020
Reported Value Measurement [Member]
Notes payable, net (1)	[1]	$ 5,045,868	$ 5,044,208
Reported Value Measurement [Member] | Mortgages [Member]
Mortgages payable, net (2)	[2]	295,613	311,272
Estimate of Fair Value Measurement [Member]
Notes payable, net (1)	[1]	5,306,905	5,486,953
Estimate of Fair Value Measurement [Member] | Mortgages [Member]
Mortgages payable, net (2)	[2]	$ 297,860	$ 312,933

[1] The Company determined that the valuation of its Senior Unsecured Notes were classified within Level 2 of the fair value hierarchy and its unsecured revolving credit facility was classified within Level 3 of the fair value hierarchy. The estimated fair value amounts classified as Level 2, as of March 31, 2021 and December 31, 2020, were $5.3 billion and $5.5 billion, respectively.

[2] The Company determined that its valuation of its mortgages loan were classified within Level 3 of the fair value hierarchy.