Summary of Reconciles Total Consideration Transferred (Parenthetical) (Detail) - USD ($)		3 Months Ended
	Oct. 01, 2018	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Debt Instrument Carrying Amount		$ 775,218,483
Business acquisition, transaction costs		$ 260,000	$ 60,000
Strategic Storage Growth Trust, Inc
Business Acquisition [Line Items]
Cash consideration	$ 346,231,561
Cash paid to shareholders	320,000,000
Debt Instrument Carrying Amount	19,000,000
Other liabilities paid	5,000,000
Business acquisition, transaction costs	$ 1,000,000