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		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income of joint ventures, net		$ 19,000	$ 13,200	$ 35,953	$ 27,902
Kim Pru and Kim Pru II [Member]
Income of joint ventures, net		2,700	3,200	5,600	6,500
KIR [Member]
Income of joint ventures, net		9,900	7,200	18,900	16,600
CPP [Member]
Income of joint ventures, net		1,300	1,300	2,500	2,900
Other Joint Venture Programs [Member]
Income of joint ventures, net	[1]	$ 5,100	$ 1,500	$ 9,000	$ 1,900

[1] During the three months ended June 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.