Note 5 - Investments In and Advances to Real Estate Joint Ventures - The Company's Share of Net Income/(Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Prudential Investment Program [Member]
Income of joint ventures, net	[1]	$ 2,600	$ 1,900	$ 7,400	$ 7,200
KIR [Member]
Income of joint ventures, net		17,500	9,400	62,900	27,200
CPP [Member]
Income of joint ventures, net		2,500	2,600	8,200	6,700
Other Institutional Joint Ventures [Member]
Income of joint ventures, net		800	900	6,300	900
Other Joint Venture Programs [Member]
Income of joint ventures, net		3,000	5,200	9,300	12,100
Joint Ventures [Member]
Income of joint ventures, net		$ 26,360	$ 20,025	$ 94,060	$ 54,095

[1] During the nine months ended September 30, 2022, the Prudential Investment Program recognized an impairment charge on a property of $15.1 million, of which the Company’s share was $2.3 million.