Note 6 - Adjustment of Property Carrying Values and Real Estate Under Development (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Expense (Benefit)	$ 3,939,000	$ 21,330,000	$ 3,208,000
Number of Real Estate Properties	28
Real Estate Investment Property, Net (in Dollars)	7,201,825,069	7,078,167,000
Sold [Member] | Impairments [Member]
Number of Real Estate Properties			4
Operating Properties [Member] | Impairments [Member]
Impairment of Real Estate (in Dollars)		3,900,000
Income Tax Expense (Benefit)		1,100,000
Number of Real Estate Properties	4	2
Operating Properties [Member]
Number of Real Estate Properties	24
Pre-Impairment [Member] | Impairments [Member]
Real Estate Investment Property, Net (in Dollars)	86,600,000	9,200,000
Impairments [Member] | Ground Up Developments [Member]
Impairment of Real Estate (in Dollars)			11,700,000
Impairments [Member]
Real Estate Investment Property, Net (in Dollars)	52,500,000
Impairments [Member] | Land Parcels [Member]
Number of Real Estate Properties		1
Impairments [Member] | Under Development [Member]
Number of Real Estate Properties			1
Impairments [Member] | Ground Up Developments [Member]
Number of Real Estate Properties			1
Impairments [Member] | Segment, Discontinued Operations [Member]
Impairment of Real Estate (in Dollars)			5,200,000
Impairments [Member]
Impairment of Real Estate (in Dollars)	34,100,000		8,700,000
Income Tax Expense (Benefit)	10,700,000	400,000	0
Number of Real Estate Properties			7
Real Estate Investment Property, Net (in Dollars)		$ 5,300,000
Ground Up Developments [Member]
Number of Real Estate Properties	3