Commitment and Contingencies - Additional Information (Detail) $ in Thousands				6 Months Ended
	Aug. 01, 2019 USD ($) Property	Jul. 02, 2019 USD ($) Property	Jul. 01, 2019 USD ($) Property	Jun. 30, 2019 USD ($) Property Facility
Commitment And Contingencies [Line Items]
Number of storage facilities to be acquired | Property				16
Aggregate purchase price of business to be acquired | $				$ 202,400
Number of storage facilities acquired | Property				6
Cash payments for property acquisition | $				$ 95,819
Number of remaining facilities to be purchased | Facility				4
Expansion and enhancement contracts | $				$ 38,500
Self-storage Facilities [Member]
Commitment And Contingencies [Line Items]
Number of storage facilities sold | Property				32
Subsequent Event [Member]
Commitment And Contingencies [Line Items]
Number of storage facilities acquired | Property	6		12
Cash payments for property acquisition | $	$ 76,100		$ 134,800
Subsequent Event [Member] | Self-storage Facilities [Member]
Commitment And Contingencies [Line Items]
Number of storage facilities sold | Property		32
Cash consideration | $		$ 212,000