Note 8 - Other Real Estate Investments (Details) - Preferred Equity Investments - Income Statement Disclosures - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	[1]	Sep. 30, 2014	[1]	Jun. 30, 2014	[1]	Mar. 31, 2014	[1]	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Note 8 - Other Real Estate Investments (Details) - Preferred Equity Investments - Income Statement Disclosures [Line Items]
Revenues from rental property	$ 296,501	$ 283,387	$ 289,080	$ 275,506	$ 255,749		$ 246,555		$ 237,432		$ 219,152		$ 1,144,474	$ 958,888	$ 825,210
Operating expenses													(823,197)	(683,582)	(612,061)
Interest expense													(218,891)	(203,759)	(212,240)
Depreciation and amortization													(344,527)	(258,074)	(224,713)
Other expense, net													2,234	(8,544)	1,195
Income from continuing operations													343,572	310,315	249,466
Discontinued Operations:
													6	37,612	52,246
Net income													900,143	435,880	241,353
Preferred Equity Investments [Member]
Note 8 - Other Real Estate Investments (Details) - Preferred Equity Investments - Income Statement Disclosures [Line Items]
Revenues from rental property													122,100	146,000	159,500
Operating expenses													(35,600)	(47,000)	(34,800)
Interest expense													(35,700)	(47,100)	(55,200)
Depreciation and amortization													(11,400)	(19,200)	(24,000)
Other expense, net													(9,200)	(7,200)	(7,100)
Income from continuing operations													30,200	25,500	38,400
Discontinued Operations:
Gain on disposition of properties													0	31,500	20,800
													0	31,500	20,800
Gain on sale of operating properties													6,000	0	0
Net income													$ 36,200	$ 57,000	$ 59,200

[1] All periods have been adjusted to reflect the impact of operating properties sold during 2014, which are reflected in the caption Discontinued operations on the accompanying Consolidated Statements of Income. Upon the adoption of ASU 2014-08 on January 1, 2015, individual property dispositions will no longer qualify as a discontinued operation under the new guidance.