Investments in Real Estate - Summary of Acquired Wholly Owned Industrial Properties (Detail) $ in Thousands		3 Months Ended		4 Months Ended	9 Months Ended
	Mar. 05, 2020 building shares	Sep. 30, 2020 USD ($) ft² a building	Mar. 31, 2020 USD ($)	Jun. 19, 2020 USD ($) building	Sep. 30, 2020 USD ($) ft² building	Sep. 30, 2019 USD ($)
Real Estate [Line Items]
Rentable Square Feet | ft²		1,583,121			1,583,121
Number of Buildings | building		40			40
Acquisition Purchase Price		$ 352,558			$ 352,558
Assumption of debt in connection with acquisition of real estate including loan premium					48,759	$ 0
Noncontrolling Interests | Operating Partnership
Real Estate [Line Items]
Limited Partners' Capital Account, Units Issued | shares	1,406,170
Properties Acquired on March 5, 2020 and June 19, 2020
Real Estate [Line Items]
Number of Buildings | building	10			1
Acquisition Purchase Price		$ 214,200			214,200
Purchase price					$ 60,400
Payments for Deposits on Real Estate Acquisitions			$ 10,000
Properties Acquired on March 5, 2020 and June 19, 2020 | Series 2 CPOP Units
Real Estate [Line Items]
Acquisition, preferred units issued (in units) | shares	906,374
Preferred Unit, Distribution Rate, Percentage	4.00%
Properties Acquired on March 5, 2020 and June 19, 2020 | Secured Debt
Real Estate [Line Items]
Assumption of debt in connection with acquisition of real estate including loan premium				$ 47,500
701-751 Kingshill Place
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		169,069			169,069
Number of Buildings | building		6			6
Acquisition Purchase Price		$ 33,251			$ 33,251
2601-2641 Manhattan Beach Blvd
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		126,726			126,726
Number of Buildings | building		6			6
Acquisition Purchase Price		$ 39,481			$ 39,481
2410-2420 Santa Fe Avenue
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		112,000			112,000
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 35,737			$ 35,737
11600 Los Nietos Road
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		103,982			103,982
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 16,626			$ 16,626
5160 Richton Street
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		94,976			94,976
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 15,653			$ 15,653
2205 126th Street
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		63,532			63,532
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 17,712			$ 17,712
11832-11954 La Cienega Blvd
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		63,462			63,462
Number of Buildings | building		4			4
Acquisition Purchase Price		$ 19,664			$ 19,664
7612-7642 Woodwind Drive
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		62,377			62,377
Number of Buildings | building		3			3
Acquisition Purchase Price		$ 13,780			$ 13,780
960-970 Knox Street
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		39,400			39,400
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 9,939			$ 9,939
25781 Atlantic Ocean Drive
Real Estate [Line Items]
Date of Acquisition					Mar. 05, 2020
Rentable Square Feet | ft²		27,960			27,960
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 5,516			$ 5,516
Brady Way
Real Estate [Line Items]
Date of Acquisition					Apr. 01, 2020
Rentable Square Feet | ft²		0			0
Number of Buildings | building		0			0
Acquisition Purchase Price		$ 874			$ 874
Number Of Acres | a		1
720-750 Vernon Avenue
Real Estate [Line Items]
Date of Acquisition					Apr. 03, 2020
Rentable Square Feet | ft²		71,692			71,692
Number of Buildings | building		3			3
Acquisition Purchase Price		$ 15,515			$ 15,515
6687 Flotilla Street
Real Estate [Line Items]
Date of Acquisition					May 05, 2020
Rentable Square Feet | ft²		120,000			120,000
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 21,000			$ 21,000
1055 Sandhill Avenue
Real Estate [Line Items]
Date of Acquisition					May 28, 2020
Rentable Square Feet | ft²		0			0
Number of Buildings | building		0			0
Acquisition Purchase Price		$ 14,453			$ 14,453
22895 Eastpark Drive
Real Estate [Line Items]
Date of Acquisition					Jun. 19, 2020
Rentable Square Feet | ft²		34,950			34,950
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 6,844			$ 6,844
8745-8775 Production Avenue
Real Estate [Line Items]
Date of Acquisition					Jun. 19, 2020
Rentable Square Feet | ft²		46,820			46,820
Number of Buildings | building		2			2
Acquisition Purchase Price		$ 7,850			$ 7,850
15580 Slover Avenue
Real Estate [Line Items]
Date of Acquisition					Jun. 26, 2020
Rentable Square Feet | ft²		60,127			60,127
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 9,958			$ 9,958
15650-15700 Avalon Blvd
Real Estate [Line Items]
Date of Acquisition					Jul. 01, 2020
Rentable Square Feet | ft²		166,088			166,088
Number of Buildings | building		2			2
Acquisition Purchase Price		$ 28,079			$ 28,079
11308-11350 Penrose Street
Real Estate [Line Items]
Date of Acquisition					Jul. 01, 2020
Rentable Square Feet | ft²		151,604			151,604
Number of Buildings | building		2			2
Acquisition Purchase Price		$ 25,427			$ 25,427
11076-11078 Fleetwood Street
Real Estate [Line Items]
Date of Acquisition					Jul. 01, 2020
Rentable Square Feet | ft²		26,040			26,040
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 4,711			$ 4,711
11529-11547 Tuxford Street
Real Estate [Line Items]
Date of Acquisition					Jul. 01, 2020
Rentable Square Feet | ft²		29,730			29,730
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 5,005			$ 5,005
12133 Greenstone Avenue
Real Estate [Line Items]
Date of Acquisition					Jul. 17, 2020
Rentable Square Feet | ft²		12,586			12,586
Number of Buildings | building		1			1
Acquisition Purchase Price		$ 5,483			$ 5,483