Note 16 - Fair Value Disclosure of Financial Instruments - Estimate of Fair Value Differs From Carrying Amounts (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Mortgages [Member]
Mortgages payable (3)		$ 2,100	$ 1,400
Reported Value Measurement [Member]
Notes payable (2)	[1]	3,927,251	3,761,328
Reported Value Measurement [Member] | Mortgages [Member]
Mortgages payable (3)	[2]	1,139,117	1,614,982
Reported Value Measurement [Member] | Marketable Securities [Member]
Marketable securities (1)	[3]	8,101	7,565
Estimate of Fair Value Measurement [Member]
Notes payable (2)	[1]	3,890,797	3,820,205
Estimate of Fair Value Measurement [Member] | Mortgages [Member]
Mortgages payable (3)	[2]	1,141,047	1,629,760
Estimate of Fair Value Measurement [Member] | Marketable Securities [Member]
Marketable securities (1)	[3]	$ 8,101	$ 7,564

[1] The Company determined that its valuation of these Notes payable was classified within Level 2 of the fair value hierarchy.

[2] The Company determined that its valuation of these Mortgages payable was classified within Level 3 of the fair value hierarchy.

[3] As of December 31, 2016 and 2015, the Company determined that $6.5 million and $5.9 million, respectively, of the Marketable securities estimated fair value were classified within Level 1 of the fair value hierarchy and the remaining $1.6 million and $1.7 million, respectively, were classified within Level 3 of the fair value hierarchy.