REAL ESTATE PROPERTIES - Summary (Details)		12 Months Ended
		Dec. 31, 2021 USD ($) ft² a	Dec. 31, 2020 USD ($) ft²	Dec. 31, 2019 USD ($) ft² a
Real Estate Properties [Line Items]
Percentage of occupancy to qualify as value-add property		75.00%
Percentage of acquisition price to be spent on capital items to qualify as value-add property		20.00%
Land		$ 544,505,000	$ 502,739,000
Buildings and building improvements		2,408,944,000	2,120,731,000
Tenant and other mprovements		570,627,000	524,954,000
Right-of-Use Assets - Ground Leases (operating)	[1]	22,635,000	11,073,000
Development and value-add properties		504,614,000	359,588,000
Total real estate properties acquired		4,051,325,000	3,519,085,000
Real Estate Investment Property, Accumulated Depreciation		1,035,617,000	955,328,000
Real Estate Investment Property, Net		$ 3,015,708,000	$ 2,563,757,000
2021 acquisitions
Real Estate Properties [Line Items]
Size | ft²	[2]	1,806,000
Purchase price	[2]	$ 279,225,000
2021 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]	760,000
Purchase price	[3]	$ 108,149,000
2021 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]	1,046,000
Purchase price	[4]	$ 171,076,000
2021 value-add properties acquired | Development land
Real Estate Properties [Line Items]
Size | a		365.8
Purchase price		$ 41,065,000
2020 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]		347,000
Purchase price	[3]		$ 48,656,000
2020 Acquisitions [Member]
Real Estate Properties [Line Items]
Size | ft²	[2]		509,000
Purchase price	[2]		$ 76,518,000
2019 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]			884,000
Purchase price	[3]			$ 141,886,000
Size (in acres) of land | a	[3]			48.1
2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			890,000
Purchase price	[4]			$ 92,623,000
2019 Acquisitions [Member]
Real Estate Properties [Line Items]
Size | ft²	[2]			1,774,000
Purchase price	[2]			$ 234,509,000
Size (in acres) of land | a				48.1
Southpark Distribution Center 2 | 2021 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]	79,000
Date of Acquisition	[3]	Jun. 10, 2021
Purchase price	[3]	$ 9,177,000
DFW Global Logistics Centre | 2021 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]	611,000
Date of Acquisition	[3]	Aug. 26, 2021
Purchase price	[3]	$ 89,829,000
Progress Center 3 | 2021 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]	50,000
Date of Acquisition	[3]	Sep. 23, 2021
Purchase price	[3]	$ 5,000,000
Texas Avenue | 2021 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]	20,000
Date of Acquisition	[3]	Oct. 15, 2021
Purchase price	[3]	$ 4,143,000
Access Point 1 | 2021 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]	156,000
Date of Acquisition	[4]	Jan. 15, 2021
Purchase price	[4]	$ 10,501,000
Northpoint 200 [Member] | 2021 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]	79,000
Date of Acquisition	[4]	Jan. 21, 2021
Purchase price	[4]	$ 6,516,000
Access Point 2 | 2021 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]	159,000
Date of Acquisition	[4]	May 19, 2021
Purchase price	[4]	$ 10,743,000
Cherokee 75 Business Center 2 | 2021 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]	105,000
Date of Acquisition	[4]	Jun. 17, 2021
Purchase price	[4]	$ 8,837,000
Siempre Viva 3-6 | 2021 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]	547,000
Date of Acquisition	[4]	Dec. 01, 2021
Purchase price	[4]	$ 134,479,000
Wells Point One | 2020 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]		50,000
Date of Acquisition	[3]		Feb. 28, 2020
Purchase price	[3]		$ 6,231,000
Cherokee 75 Business Center I | 2020 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]		85,000
Date of Acquisition	[3]		Dec. 15, 2020
Purchase price	[3]		$ 8,323,000
The Rock at Star Business Park | 2020 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]		212,000
Date of Acquisition	[3]		Dec. 17, 2020
Purchase price	[3]		$ 34,102,000
Rancho Distribution Center | 2020 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]		162,000
Date of Acquisition	[4]		Oct. 15, 2020
Purchase price	[4]		$ 27,862,000
Airways Business Center [Member] | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]			382,000
Date of Acquisition	[3]			May 20, 2019
Purchase price	[3]			$ 48,327,000
Miramar Land [Member] | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | a	[3],[5]			6.5
Date of Acquisition	[3],[5]			May 31, 2019
Purchase price	[3],[5]			$ 13,386,000
385 Business Park [Member] | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]			155,000
Date of Acquisition	[3]			Jul. 31, 2019
Purchase price	[3]			$ 13,900,000
Grand Oaks 75 Business Center I [Member] | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]			169,000
Date of Acquisition	[3]			Sep. 06, 2019
Purchase price	[3]			$ 17,974,000
Siempre Viva Distribution Center II [Member] | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]			60,000
Date of Acquisition	[3]			Oct. 04, 2019
Purchase price	[3]			$ 8,621,000
Rocky Point Distribution Center I [Member] | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | ft²	[3]			118,000
Date of Acquisition	[3]			Dec. 17, 2019
Purchase price	[3]			$ 24,396,000
Otay Mesa Land | 2019 operating properties acquired
Real Estate Properties [Line Items]
Size | a	[3],[5]			41.6
Date of Acquisition	[3],[5]			Dec. 31, 2019
Purchase price	[3],[5]			$ 15,282,000
Logistics Center 6 & 7 [Member] | 2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			142,000
Date of Acquisition	[4]			Apr. 23, 2019
Purchase price	[4]			$ 12,960,000
Arlington Tech Centre 1 & 2 [Member] | 2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			151,000
Date of Acquisition	[4]			Aug. 16, 2019
Purchase price	[4]			$ 12,615,000
Grand Oaks 75 2 [Member] | 2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			150,000
Date of Acquisition	[4]			Sep. 06, 2019
Purchase price	[4]			$ 12,815,000
Interstate Commons II [Member] | 2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			142,000
Date of Acquisition	[4]			Oct. 21, 2019
Purchase price	[4]			$ 9,386,000
Southwest Commerce Center [Member] | 2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			196,000
Date of Acquisition	[4]			Oct. 30, 2019
Purchase price	[4]			$ 25,609,000
Rocky Point Distribution Center II [Member] | 2019 value-add properties acquired
Real Estate Properties [Line Items]
Size | ft²	[4]			109,000
Date of Acquisition	[4]			Dec. 17, 2019
Purchase price	[4]			$ 19,238,000

[1] See Ground Leases discussion below for information regarding the Company’s right of use assets for ground leases.

[2] Excludes development land as detailed below.

[3] Operating properties are defined as stabilized real estate properties (land including buildings and improvements) in the Company’s operating portfolio; included in Real estate properties on the Consolidated Balance Sheets.

[4] 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.

[5] Land which was leased at the time of acquisition and including in the operating portfolio