Note 21 - Income Taxes - GAAP Net Income/(Loss) to Taxable Income Reconciliation (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
GAAP net income (loss)		$ 109,419	$ 83,990	$ 101,027	$ 116,169	$ 88,161	$ 100,158	$ 165,386	$ 144,090	$ 410,605	$ 497,795	$ 426,075
Net book depreciation in excess of tax depreciation										56,094	46,754	122,043
Capitalized leasing/legal commissions										0	(15,268)	(7,102)
Deferred/prepaid/above-market and below-market rents, net										(33,518)	(23,466)	(29,364)
Fair market value debt amortization										(4,412)	(5,268)	(8,495)
Book/tax differences from executive compensation (2)	[1]									6,026	5,460	2,396
Book/tax differences from investments in and advances to real estate joint ventures										(606)	26,263	(24,992)
Book/tax differences from sale of properties										18,692	(13,612)	(86,629)
Book adjustment to property carrying values and marketable equity securities										31,980	59,866	51,309
Taxable currency exchange gains/(losses), net										(33)	929	(780)
Tangible property regulation deduction										0	(40,361)	(52,809)
GAAP gain on change in control of joint venture interests										(137)	(6,800)	(71,160)
Dividends from TRSs										3,331	526	1,226
Other book/tax differences, net										(3,166)	775	2,056
Adjusted REIT taxable income										484,852	527,045	311,196
Share-based Payment Arrangement, Option [Member]
Sharebased Compensation										(1,121)	(112)	(172)
GAAP Net Loss/(Income) of Taxable REIT Subsidiaries [Member]
GAAP net income (loss)										1,117	(2,436)	(12,406)
GAAP Net Income From REIT Operations [Member]
GAAP net income (loss)	[2]									$ 411,722	$ 495,359	$ 413,669

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