Note 12 - Fair Value Measurements - Estimate of Fair Value Differs From Carrying Amounts (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Reported Value Measurement [Member]
Notes payable, net (1)	[1]	$ 4,420,370	$ 4,381,456
Reported Value Measurement [Member] | Mortgages [Member]
Mortgages and construction loan payable, net (2)	[2]	485,132	492,416
Estimate of Fair Value Measurement [Member]
Notes payable, net (1)	[1]	4,484,767	4,126,450
Estimate of Fair Value Measurement [Member] | Mortgages [Member]
Mortgages and construction loan payable, net (2)	[2]	$ 487,889	$ 486,341

[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 June 30, 2019 and December 31, 2018, were $4.4 billion and $4.0 billion, respectively. The estimated fair value amounts classified as Level 3, as of June 30, 2019 and December 31, 2018, were $133.7 million and $97.6 million, respectively.

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