Rental Property - Acquisitions (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020 USD ($) ft² building	Jun. 30, 2020 USD ($) ft² building	Mar. 31, 2020 USD ($) ft² building	Sep. 30, 2020 USD ($) ft² building
Business Acquisition [Line Items]
Area (in square feet)	92,300,000			92,300,000
Acquisitions 2020
Business Acquisition [Line Items]
Area (in square feet)	2,351,350			2,351,350
Number of properties | building				16
Business Combination, Consideration Transferred | $				$ 195,939
Acquistions Q1 2020
Business Acquisition [Line Items]
Area (in square feet)			1,599,389
Number of properties | building			9
Business Combination, Consideration Transferred | $			$ 119,343
Canton, MI - 1-10-20
Business Acquisition [Line Items]
Area (in square feet)			491,049
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 29,543
Rochester, NY - 1-10-20
Business Acquisition [Line Items]
Area (in square feet)			124,850
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 8,565
Hudson, WI - 2-6-20
Business Acquisition [Line Items]
Area (in square feet)			139,875
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 10,460
McClellan, CA - 2-6-20
Business Acquisition [Line Items]
Area (in square feet)			160,534
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 18,468
Richmond, VA - 2-6-20
Business Acquisition [Line Items]
Area (in square feet)			78,128
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 5,481
Muskego, WI - 2-7-20
Business Acquisition [Line Items]
Area (in square feet)			81,230
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 7,219
Warren, MI - 2-11-20
Business Acquisition [Line Items]
Area (in square feet)			311,123
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 23,141
Langhorne, PA - 3-9-20
Business Acquisition [Line Items]
Area (in square feet)			78,000
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 6,571
Tulsa, OK - 3-9-20
Business Acquisition [Line Items]
Area (in square feet)			134,600
Number of properties | building			1
Business Combination, Consideration Transferred | $			$ 9,895
Acquisitions Q2 2020
Business Acquisition [Line Items]
Area (in square feet)		122,280
Number of properties | building		2
Business Combination, Consideration Transferred | $		$ 11,914
Rancho Cordova, CA 6-11-20
Business Acquisition [Line Items]
Area (in square feet)		54,463
Number of properties | building		1
Business Combination, Consideration Transferred | $		$ 5,730
Schaumburg, IL 6-29-20
Business Acquisition [Line Items]
Area (in square feet)		67,817
Number of properties | building		1
Business Combination, Consideration Transferred | $		$ 6,184
Acquisitions Q3 2020
Business Acquisition [Line Items]
Area (in square feet)	629,681			629,681
Number of properties | building	5
Business Combination, Consideration Transferred | $	$ 64,682
Mount Laurel, NJ - 8-31-20
Business Acquisition [Line Items]
Area (in square feet)	112,294			112,294
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 8,427
Clinton, PA - 9-3-20
Business Acquisition [Line Items]
Area (in square feet)	125,000			125,000
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 15,580
Clinton, PA - 9-24-20
Business Acquisition [Line Items]
Area (in square feet)	66,387			66,387
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 6,685
Charlotte, NC - 9-28-20
Business Acquisition [Line Items]
Area (in square feet)	50,000			50,000
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 5,729
Twinsburg, OH - 9-30-20
Business Acquisition [Line Items]
Area (in square feet)	276,000			276,000
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 28,261