Note 9 - Subsequent Events (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 31, 2012	Apr. 30, 2012 sqft	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012	Jul. 10, 2012 sqft
Common Stock, Dividends, Per Share, Declared (in Dollars per share)			$ 0.13
Distributions Per General Partnership Unit Outstanding (in Dollars per share)			$ 0.13
Payments of Dividends			$ 13,687
Number of Vacant Properties Sold During Period	3	4		1	10
Area of Real Estate Property (in Square feet)		145,000				149,000
Proceeds from Divestiture of Businesses	18,500	19,350
Gain (Loss) on Disposition of Property	$ 3,389	$ 7,989