Note 21 - Income Taxes - GAAP Net Income/(Loss) to Taxable Income Reconciliation (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
GAAP net income (loss)		$ 88,161	$ 100,158	$ 165,386	$ 144,090	$ 84,896	$ 121,030	$ 143,416	$ 76,733	$ 497,795	$ 426,075	$ 378,850
Net book depreciation in excess of tax depreciation										61,363	122,043	65,194
Capitalized leasing/legal commissions										(15,268)	(7,102)	(11,984)
Deferred/prepaid/above-market and below-market rents, net										(23,437)	(29,364)	(34,097)
Fair market value debt amortization										(5,268)	(8,495)	(15,901)
Book/tax differences from executive compensation (2)	[1]									5,460	2,396
Book/tax differences from investments in and advances to real estate joint ventures										7,921	(23,802)	(20,739)
Book/tax differences from sale of properties										(2,889)	(86,629)	(93,704)
Book adjustment to property carrying values and marketable equity securities										69,804	51,309	11,161
Taxable currency exchange gains/(losses), net										1,260	(780)	(8,962)
Tangible property regulation deduction										(49,209)	(52,809)	(28,954)
GAAP gain on change in control of joint venture interests										(6,800)	(71,160)	(57,385)
Valuation allowance against net deferred tax assets												51,939
Other book/tax differences, net										(10,351)	3,282	28
Adjusted REIT taxable income										526,912	311,195	236,853
Employee Stock Option [Member]
Sharebased Compensation										(112)	(172)	(11,301)
GAAP Net Loss/(Income) of Taxable REIT Subsidiaries [Member]
GAAP net income (loss)										(3,357)	(13,597)	12,708
GAAP Net Income From REIT Operations [Member]
GAAP net income (loss)	[2]									$ 494,438	$ 412,478	$ 391,558

[1] In accordance with the Tax Cuts and Jobs Act, effective for tax years beginning on January 1, 2018, under Section 162(m) of the Code placed a $1.0 million limit on the amount a company can deduct for executive compensation for their CEO, CFO and other three most highly paid executives.

[2] All adjustments to "GAAP net income from REIT operations" are net of amounts attributable to noncontrolling interests and TRSs.