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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income of joint ventures, net		$ 16,500	$ 9,100	$ 52,486	$ 37,044
Kim Pru and Kim Pru II [Member]
Income of joint ventures, net		3,000	3,200	8,500	9,700
KIR [Member]
Income of joint ventures, net		8,000	8,200	26,900	24,700
CPP [Member]
Income of joint ventures, net		1,200	1,300	3,700	4,300
Other Joint Venture Programs [Member]
Income of joint ventures, net	[1]	$ 4,300	$ (3,600)	$ 13,400	$ (1,700)

[1] During the nine months ended September 30, 2018, a joint venture investment distributed cash proceeds resulting from the refinancing of an existing loan of which the Company's share was $3.6 million. This distribution was in excess of the Company's carrying basis in this joint venture investment and as such was recognized as income.