Investment in Storage Facilities - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014 Facility	Mar. 31, 2013
Real Estate [Abstract]
Number of storage facilities acquired	7
Cash paid for properties acquired	$ 94,601,000
Deposits paid at the time of contract	5,500,000
Amortization period for in-place customer leases on a straight-line basis	12 months
Amortization expense related to in-place customer leases	700,000	900,000
Amortization expense for the year	$ 2,500,000