Note 7 - Investment In and Advances to Real Estate Joint Ventures - The Company's Share of Net Income/(Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Prudential Investment Program [Member]
Income of joint ventures, net	[1]	$ 9,600	$ 17,500	$ 9,000
KIR [Member]
Income of joint ventures, net		70,300	36,900	30,500
CPP [Member]
Income of joint ventures, net		10,600	9,200	5,600
Other Institutional Joint Ventures [Member]
Income of joint ventures, net		7,000	1,700	0
Other Joint Venture Programs [Member]
Income of joint ventures, net		12,000	19,500	2,300
Joint Ventures [Member]
Income of joint ventures, net		$ 109,481	$ 84,778	$ 47,353

[1] During the year ended December 31, 2019, the Prudential Investment Program recognized an impairment charge on a property of $29.9 million, of which the Company’s share was $3.7 million.