Note 3 - Discontinued Operations (Detail) (USD $)	Mar. 31, 2013 sqft		Dec. 31, 2012
(in Square Feet)	1,063,000	[1]
Real Estate Investment Property, Accumulated Depreciation	$ 1,801,679,000		$ 1,745,462,000
Fair Value Of Real Estate	14,706,000		52,505,000
Assets Held-for-sale [Member] | Operating Properties [Member]
Number of Real Estate Properties	1
Assets Held-for-sale [Member] | Remaining [Member]
Real Estate Held-for-sale	200,000
Real Estate Investment Property, Accumulated Depreciation	900,000
Assets Held-for-sale [Member]
(in Square Feet)	14,600
Fair Value Of Real Estate	$ 200,000
Operating Properties [Member] | Sold [Member]
Number of Real Estate Properties	1

[1] Gross leasable area ("GLA")