Note 2 - Real Estate - Components of Rental Property (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Land		$ 2,845,186	$ 2,728,257
Buildings and improvements:
Buildings and improvements		8,827,861	8,661,362
Above-market leases		150,207	155,451
In-place leases and tenant relationships		543,342	528,539
		11,673,047	11,389,619
Accumulated depreciation and amortization (1)	[1]	(2,278,292)	(2,115,320)
Total		9,394,755	9,274,299
Land [Member]
Land		2,786,255	2,660,722
Undeveloped Land [Member]
Land		58,931	67,535
Building [Member]
Buildings and improvements:
Buildings and improvements		5,790,681	5,643,629
Building Improvements [Member]
Buildings and improvements:
Buildings and improvements		1,562,439	1,559,652
Tenant Improvements [Member]
Buildings and improvements:
Buildings and improvements		733,993	727,036
Fixtures And Leasehold Improvements [Member]
Buildings and improvements:
Buildings and improvements		$ 47,199	$ 47,055

[1] At December 31, 2016 and 2015, the Company had accumulated amortization relating to in-place leases, tenant relationships and above-market leases aggregating $409,062 and $357,581, respectively.