Note 12 - Fair Value Measurements - Estimate of Fair Value Differs From Carrying Amounts (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Reported Value Measurement [Member]
Notes payable, net (1)	[1]	$ 4,383,413	$ 4,381,456
Reported Value Measurement [Member] | Mortgages [Member]
Mortgages and construction loan payable, net (2)	[2]	485,341	492,416
Estimate of Fair Value Measurement [Member]
Notes payable, net (1)	[1]	4,302,177	4,126,450
Estimate of Fair Value Measurement [Member] | Mortgages [Member]
Mortgages and construction loan payable, net (2)	[2]	$ 483,412	$ 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 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, 2019 and December 31, 2018, were $4.2 billion and $4.0 billion, respectively. The estimated fair value amounts classified as Level 3 as of March 31, 2019 and December 31, 2018, were $97.9 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.