REAL ESTATE PROPERTIES REAL ESTATE PROPERTIES 2 (Details)		12 Months Ended
		Dec. 31, 2017 USD ($) ft²	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2015 USD ($) ft²
Sales of real estate properties [Line Items]
Net Sales Price of Real Estate Sold		$ 37,557,000	$ 73,725,000
Basis		15,702,000	31,555,000
Gain, net of loss, on Sales of Real Estate Investments		$ 21,855,000	$ 42,170,000	$ 2,903,000
Stemmons Circle [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²		99,000
Date Of Property Sale		5/12/17
Net Sales Price of Real Estate Sold		$ 5,051,000
Basis		1,329,000
Gain, net of loss, on Sales of Real Estate Investments		$ 3,722,000
Techway Southwest I, II, III, & IV [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²		415,000
Date Of Property Sale		6/19/17
Net Sales Price of Real Estate Sold		$ 32,506,000
Basis		14,373,000
Gain, net of loss, on Sales of Real Estate Investments		18,133,000
Northwest Point Distribution and Service Centers [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			232,000
Date Of Property Sale			2/12/16
Net Sales Price of Real Estate Sold			$ 15,189,000
Basis			5,080,000
Gain, net of loss, on Sales of Real Estate Investments			$ 10,109,000
North Stemmons III [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			60,000
Date Of Property Sale			3/4/16
Net Sales Price of Real Estate Sold			$ 3,131,000
Basis			1,908,000
Gain, net of loss, on Sales of Real Estate Investments			$ 1,223,000
North Stemmons II [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			26,000
Date Of Property Sale			4/12/16
Net Sales Price of Real Estate Sold			$ 1,203,000
Basis			765,000
Gain, net of loss, on Sales of Real Estate Investments			$ 438,000
Lockwood Distribution Center [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			392,000
Date Of Property Sale			4/18/16
Net Sales Price of Real Estate Sold			$ 14,024,000
Basis			4,154,000
Gain, net of loss, on Sales of Real Estate Investments			$ 9,870,000
West Loop Distribution Center 1 & 2 [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			161,000
Date Of Property Sale			4/19/16
Net Sales Price of Real Estate Sold			$ 13,154,000
Basis			3,564,000
Gain, net of loss, on Sales of Real Estate Investments			$ 9,590,000
America Plaza [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			121,000
Date Of Property Sale			4/28/16
Net Sales Price of Real Estate Sold			$ 7,938,000
Basis			3,378,000
Gain, net of loss, on Sales of Real Estate Investments			$ 4,560,000
Interstate Commons Distribution Center I and II [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			142,000
Date Of Property Sale			5/31/16
Net Sales Price of Real Estate Sold			$ 9,906,000
Basis			3,568,000
Gain, net of loss, on Sales of Real Estate Investments			$ 6,338,000
Castilian Research Center [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²	[1]		30,000
Date Of Property Sale	[1]		6/28/16
Net Sales Price of Real Estate Sold	[1]		$ 7,698,000
Basis	[1]		7,513,000
Gain, net of loss, on Sales of Real Estate Investments	[1]		$ 185,000
Memphis I [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²			92,000
Date Of Property Sale			12/16/16
Net Sales Price of Real Estate Sold			$ 1,482,000
Basis			1,625,000
Gain, net of loss, on Sales of Real Estate Investments			(143,000)
Ambassador Row Warehouse (one building sold in 2015) [Member]
Sales of real estate properties [Line Items]
Size (in square feet) of property sold | ft²				185,000
Date Of Property Sale				4/13/15
Net Sales Price of Real Estate Sold				$ 4,998,000
Basis				2,095,000
Gain, net of loss, on Sales of Real Estate Investments				2,903,000
Land [Member]
Sales of real estate properties [Line Items]
Proceeds from Sale of Property, Plant, and Equipment		3,778,000	5,400,000	170,000
Gain on sales of land		$ 293,000	$ 733,000	$ 123,000
Castilian Research Center [Member]
Sales of real estate properties [Line Items]
Less Than Wholly Owned Joint Venture Investment Ownership Percentage				80.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners			20.00%

[1] EastGroup owned 80% of Castilian Research Center through a joint venture. The information shown for this transaction also includes the 20% attributable to the Company's noncontrolling interest partner.