Note 23 - Supplemental Financial Information (Details) - Quarterly Results of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Results of Operations [Abstract]
Revenues from rental properties (1)	$ 255,749	[1]	$ 246,555	[1]	$ 237,432	[1]	$ 219,152	[1]	$ 217,363	[1]	$ 205,300	[1]	$ 203,080	[1]	$ 199,467	[1]	$ 958,888	$ 825,210	$ 755,851
Net income attributable to the Company	$ 52,781		$ 194,708		$ 89,512		$ 87,000		$ 61,609		$ 55,763		$ 51,139		$ 67,770		$ 424,001	$ 236,281	$ 266,073
Net income per common share:
Basic	$ 0.09		$ 0.44		$ 0.18		$ 0.18		$ 0.11		$ 0.10		$ 0.09		$ 0.13		$ 0.89	$ 0.43	$ 0.42
Diluted	$ 0.09		$ 0.44		$ 0.18		$ 0.18		$ 0.11		$ 0.10		$ 0.09		$ 0.13		$ 0.89	$ 0.43	$ 0.42

[1] All periods have been adjusted to reflect the impact of operating properties sold during 2014 and 2013, which are reflected in the caption Discontinued operations on the accompanying Consolidated Statements of Income.