Note 14 - Noncontrolling Interests (Details Textual) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) $ / shares shares		Dec. 31, 2016 USD ($)	Dec. 31, 2007 USD ($) shares	Dec. 31, 2006 USD ($) $ / shares shares	Sep. 20, 2017
Noncontrolling Interest, Change in Redemption Value		$ 7,521		[1]
Non-controlling Interest, Annual Return	[2]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		$ 109	48,877		16,667
Redeemable Noncontrolling Interest, Equity, Carrying Amount, Total		$ 23,682	16,143		$ 86,953
PUERTO RICO
Number of Real Estate Properties		7						7
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		$ 233,000
Redeemable Noncontrolling Interest, Equity, Carrying Amount, Total		5,200	$ 5,200
PUERTO RICO | Fair Market Value Adjustments [Member]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		15,100
Preferred A Units [Member]
Non-controlling Interest, Units Redeemed | shares			79,642,697
Payments for Repurchase of Redeemable Noncontrolling Interest			$ 79,900
Payments for Repurchase of Redeemable Noncontrolling Interest, Accrued Preferred Return			$ 400
Non-controlling Interest, Par Value | $ / shares			$ 1
Non-controlling Interest, Annual Return			5.00%
Non-convertible Units [Member] | PUERTO RICO
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		158,600
Convertible Units [Member]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance							$ 5,300
Non-controlling Interest, Units | shares							138,015
Convertible Units [Member] | Fair Market Value Adjustments [Member]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance							$ 300
Convertible Units [Member] | PUERTO RICO
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		45,800
Premiums [Member] | PUERTO RICO
Noncontrolling Interest, Increase from Subsidiary Equity Issuance		$ 13,500
Capital Units, Class B [Member]
Non-controlling Interest, Units Redeemed | shares		25,970	25,000			30,000
Non-controlling Interest, Par Value | $ / shares							$ 37.24
Redeemable Noncontrolling Interest, Equity, Carrying Amount, Total		$ 24,300	$ 25,400
Non-controlling Interest, Units Issued | shares							647,758
Redeemable Units to Company Common Stock, Ratio							1
Non-controlling Interest, Cumulative Par Value		$ 1,100	$ 900			$ 1,100
Measurement Input, Cap Rate [Member]
Noncontrolling Interest, Fair Value, Measurement Input		0.05
Measurement Input, Discount Rate [Member]
Noncontrolling Interest, Fair Value, Measurement Input		0.06
KIM Lincoln, LLC [Member]
Ownership Interest in Joint Venture, Percentage			90.00%
Lincoln Square Property, LP [Member]
Ownership Interest in Joint Venture, Percentage			10.00%

[1] During 2017, KIM Lincoln, a wholly owned subsidiary of the Company, and Lincoln Member entered into a joint venture agreement wherein KIM Lincoln has a 90% controlling interest and Lincoln Member has a 10% noncontrolling interest (See Footnote 4 of the Notes to Consolidated Financial Statements). During the year ended December 31, 2018, the Company recorded an adjustment of $7.5 million to the estimated redemption fair market value of this noncontrolling interest in accordance with the provisions of the joint venture agreement and ASC 480 - Accounting for Redeemable Equity Instruments. The Company's estimated fair market value of this noncontrolling interest was based upon a discounted cash flow model, for which a capitalization rate of 5.00% and discount rate of 6.00% were utilized in the model based upon unobservable rates that the Company believes to be within a reasonable range of current market rates.

[2] These units are redeemable for cash by the holder or at the Company's option, shares of the Company's common stock, based upon the conversion calculation as defined in the agreement. These units are included in Noncontrolling interests on the Company's Consolidated Balance Sheets.