REAL ESTATE PROPERTIES (Details)		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) Integer	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Real Estate Properties [Line Items]
Number of Reporting Units | Integer				1
Depreciation Expense During the Period		$ 26,599,000	$ 24,087,000	$ 77,604,000	$ 70,989,000
Percentage of occupancy to qualify as value-add property				75.00%		75.00%
Percentage of acquisition price to be spent on capital items to qualify as value-add property				20.00%		20.00%
Real Estate Properties
Land		533,792,000		$ 533,792,000		$ 502,739,000
Building and building improvements		2,365,115,000		2,365,115,000		2,120,731,000
Tenant and other improvements		562,785,000		562,785,000		524,954,000
Right of use assets - Ground leases (operating)	[1]	23,051,000		23,051,000		11,073,000
Development and value-add properties	[2]	352,344,000		352,344,000		359,588,000
Real estate, development and value-add properties		3,837,087,000		3,837,087,000		3,519,085,000
Less accumulated depreciation		(1,031,027,000)		(1,031,027,000)		(955,328,000)
Real estate, net		$ 2,806,060,000		$ 2,806,060,000		$ 2,563,757,000
Building [Member]
Real Estate Properties [Line Items]
Property, Plant and Equipment, Useful Life				40 years
Minimum [Member] | Improvements [Member]
Real Estate Properties [Line Items]
Property, Plant and Equipment, Useful Life				3 years
Maximum [Member] | Improvements [Member]
Real Estate Properties [Line Items]
Property, Plant and Equipment, Useful Life				15 years

[1] EastGroup applies the principles of Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 842, Leases, and its related Accounting Standards Updates (“ASUs”) to account for its ground leases, which are classified as operating leases. The related operating lease liabilities for ground leases are included in Other liabilities on the Consolidated Balance Sheets.

[2] Value-add properties are defined as properties that are either acquired but not stabilized or can be converted to a higher and better use.  Acquired properties meeting either of the following two conditions are considered value-add properties:  (1) Less than 75% occupied as of the acquisition date (or will be less than 75% occupied within one year of acquisition date based on near term lease roll), or (2) 20% or greater of the acquisition cost will be spent to redevelop the property.