Note 7 - Investment and Advances in Real Estate Joint Ventures - Investment and Advances to Real Estate Joint Ventures - Income Statements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
KIR [Member]
Revenues	$ 193.6	$ 197.2	$ 198.9
Operating expenses	(51.0)	(53.3)	(55.5)
Depreciation and amortization	(38.0)	(42.2)	(39.4)
Gain on sale of operating properties	32.2	13.5	9.0
Interest expense	(28.2)	(33.3)	(35.3)
Other expense, net	(1.1)	(1.5)	(1.5)
Net income	107.5	80.4	76.2
Excluding KIR and Rio Can [Member]
Revenues	317.6	309.1	317.1
Operating expenses	(99.4)	(92.8)	(95.1)
Depreciation and amortization	(76.9)	(80.3)	(76.8)
Gain on sale of operating properties	15.0	46.8	17.0
Interest expense	(47.1)	(46.8)	(46.6)
Other expense, net	(14.2)	(2.9)	(1.5)
Net income	55.5	112.4	101.3
Impairment charges	$ (39.5)	$ (20.7)	$ (12.8)