USA Self Storage I, DST; Madison County Self Storage, DST and Southwest Colonial, DST Acquisitions - Additional Information (Detail) (USD $)	12 Months Ended		3 Months Ended	1 Months Ended		12 Months Ended	1 Months Ended	12 Months Ended		6 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2013 Store sqft	Dec. 31, 2012	Dec. 31, 2013 Southwest Colonial, DST	Feb. 28, 2013 USA Self Storage I, DST	Feb. 28, 2011 USA Self Storage I, DST Property Loan Vendor	Dec. 31, 2013 USA Self Storage I, DST Store sqft	Feb. 28, 2011 USA Self Storage I, DST Remaining ownership percentage	Dec. 31, 2013 USA Self Storage I, DST Subtrusts	Dec. 31, 2013 USA Self Storage I, DST Lease Rental Income	Dec. 31, 2012 Madison County Self Storage, DST Store Vendor Property sqft	Dec. 31, 2013 Southwest Colonial, DST Vendor Property Store sqft	Dec. 31, 2013 Southwest Colonial, DST Vendor Property Store sqft
Business Acquisition [Line Items]
Beneficial interest acquired							80.247%			52.00%	100.00%	100.00%
Business acquisition purchase price					$ 37,550,000		$ 30,100,000			$ 10,700,000	$ 27,900,000
Business acquisition cash paid					10,200,000					3,100,000	9,000,000
Number of limited partnership units issued					70,000					84,000	151,300	151,300
Loans assumed as purchase consideration					23,300,000
Number of bank loans					3
Number of properties owning subtrusts					3
Number of third-party sellers					40					13	50	50
Acquisition fees paid to the Advisor	1,700,000	2,200,000	340,000	377,000						133,000
Number of wholly-owned self storage facilities	122					10				2	5	5
Number of operation units	77,375					5,425				895	2,805	2,805
Total rental area	10,200,000					800,400				149,300	392,000	392,000
Lease expiry period								10 years
Lease expiry date						Dec. 19, 2016		Nov. 01, 2015
Rent equivalent investor return rate									7.00%
Economic benefit and obligations percentage						100.00%
Fixed interest rate on loan					5.18%					6.33%		6.36%
Term of loan					10 years					10 years		10 years
Debt payment description					The Bank of America Loans required monthly interest-only payments during the first three years of their terms and now require monthly principal-and-interest payments based on a 30-year amortization period.	The Bank of America Loans required monthly interest-only payments during the first three years of their terms and now require monthly principal-and-interest payments based on a 30-year amortization period.
Debt amortization period					30 years
Loan assumed as purchase consideration					$ 23,300,000					$ 6,500,000	$ 16,700,000
Total beneficial interest acquired										100.00%
Number of properties secured on loan										2	5	5
Maturity date of term loan										Oct. 01, 2017		Jun. 30, 2018