Investments in Unconsolidated Real Estate Entities - Schedule of Equity in Earnings of Unconsolidated Real Estate Ventures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Equity in earnings	$ 11,274	$ 14,452	$ 15,331
PRISA Self Storage LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	2,327	2,338	2,430
Storage Portfolio II JV LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	291	79	33
Storage Portfolio I LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	1,809	1,886	2,684
VRS Self Storage, LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	3,583	3,640	3,562
ESS-NYFL JV LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	(96)	0	0
WICNN JV LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	1,373	622	0
Extra Space Northern Properties Six LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	1,091	1,014	918
Alan Jathoo JV LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	(47)	(12)	0
ESS Bristol Investments LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	(262)	(152)	0
GFN JV, LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	450	22	0
PR EXR Self Storage, LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	(443)	(75)	(105)
WCOT Self Storage LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	0	359	1,033
Extra Space West Two LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	0	1,042	1,210
Extra Space West One LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings	0	2,526	2,502
Other minority owned stores
Schedule of Equity Method Investments [Line Items]
Equity in earnings	$ 1,198	$ 1,163	$ 1,064