Summary of Secured Debt (Parenthetical) (Detail) (USD $)	12 Months Ended			0 Months Ended	12 Months Ended											12 Months Ended				12 Months Ended									12 Months Ended
	Dec. 31, 2013 Property Loan	Dec. 31, 2013 Prudential Portfolio Loan Loan		Jan. 12, 2011 Dufferin - Toronto - Ontario, Canada	Dec. 31, 2013 Dufferin - Toronto - Ontario, Canada		Dec. 31, 2013 Citi Loan Property		Dec. 31, 2013 Citi Las Vegas Loan		Dec. 31, 2013 ING Loan		Dec. 31, 2013 Mississauga - Ontario, Canada		Dec. 31, 2011 Mississauga - Ontario, Canada	Dec. 31, 2013 Chantilly - VA		Dec. 31, 2013 Canadian dollars denominated loan	Sep. 30, 2012 Canadian dollars denominated loan	Dec. 31, 2013 Citi Stockade Loan - 1 Property		Dec. 31, 2013 KeyBank CMBS Loan Property		Dec. 31, 2013 Citi Stockade Loan - 2 Property		Dec. 31, 2013 Second Restated Key Bank Loan		Oct. 28, 2013 Second Restated Key Bank Loan	Dec. 31, 2013 KeyBank Revolver		Oct. 28, 2013 KeyBank Revolver
Debt Instrument [Line Items]
Numbers of discrete mortgage loans related to prudential portfolio loan	11
Numbers of properties related to prudential portfolio loan	11
Number of loans cross-collateralized with each respective loan	10
Number of loans with an interest rate of 5.43%		10
Interest rate		5.43%											5.00%					5.25%
Interest rate of remaining loan in portfolio		5.31%
Weighted average interest rate of portfolio	5.40%	5.42%
Interest rate premium over bank's floating rate				3.50%									2.00%					2.25%
Effective interest rate					5.22%
Number of existing encumbered properties							11													10		9		6
Net book value of encumbered properties							$ 50,400,000		$ 9,000,000							$ 6,900,000				$ 34,500,000		$ 42,600,000		$ 37,200,000
Prudential long beach cross collateralized by numbers of properties related to prudential portfolio loan	11
Numbers of properties related to ING loan	11
Numbers of discrete mortgage loans related to ING loan	11
Term of each individual loans											30 years
Maturity date of ING Loan											Jul. 01, 2041
Payment of loan, successive period after commencement date											5 years
Maturity date		Sep. 05, 2019	[1],[2]		May 15, 2014	[3]	Feb. 06, 2021	[4]	Jun. 06, 2021	[5]	Jul. 01, 2021	[6]	Oct. 31, 2014	[7]		Jun. 06, 2022	[8]			Oct. 01, 2022	[9]	Nov. 01, 2022	[10]	Nov. 06, 2022	[11]	Dec. 24, 2014	[12]		Oct. 25, 2016	[13]
Interest rate of spread																												4.67%	1.67%		1.67%
Notional amount for interest rate swap																										45,000,000		45,000,000
Effective interest rate on hedged portion of debt																												5.41%	2.40%
Commitment amount															$ 9,200,000				$ 9,200,000
Revolving loan maturity date																										Dec. 24, 2014			Oct. 25, 2016

[1] Ten of the loans in this portfolio loan bear an interest rate of 5.43%, and the remaining loan bears an interest rate of 5.31%. The weighted average interest rate of this portfolio is 5.42%.

[2] This portfolio loan is comprised of 11 discrete mortgage loans on 11 respective properties (Manassas, Marietta, Erlanger, Pittsburgh, Weston, Fort Lee, Oakland Park, Tempe, Phoenix II, Davie and Las Vegas I). Each of the individual loans is cross-collateralized by the other ten.

[3] On January 12, 2011, we encumbered the Dufferin property with a Canadian dollar denominated loan which bears interest at the bank's floating rate plus 3.5% (subject to a reduction in certain circumstances). The rate in effect at December 31, 2013 was 5.22%.

[4] This portfolio loan encumbers 11 properties (Biloxi, Gulf Breeze I, Alpharetta, Florence II, Jersey City, West Mifflin, Chicago - 95th St., Chicago - Western Ave., Chicago - Ogden Ave., Chicago - Roosevelt Rd. and Las Vegas IV). The net book value of the encumbered properties as of December 31, 2013 was approximately $50.4 million. Such amounts are only available to satisfy the obligations of this loan.

[5] This loan encumbers the Las Vegas VII and Las Vegas VIII properties. The net book value of the encumbered properties as of December 31, 2013 was approximately $9.0 million. Such amounts are only available to satisfy the obligations of this loan.

[6] This portfolio loan is comprised of 11 discrete mortgage loans on 11 respective properties (Peachtree City, Buford, Jonesboro, Ellenwood, Marietta II, Collegeville, Skippack, Ballston Spa, Trenton, Fredericksburg and Sandston). Each of the individual loans have an original term of 30 years and mature on July 1, 2041. ING has the option to require payment of the loan in full every five years beginning on July 1, 2021.

[7] In December 2011, we entered into a Canadian dollar denominated construction loan with an aggregate potential commitment amount of approximately $9.2 million. Such loan bears interest at the bank's floating rate, plus 2% (totaling 5.00% as of December 31, 2013).

[8] The net book value of the Chantilly property as of December 31, 2013 was approximately $6.9 million. Such amounts are only available to satisfy the obligations of this loan.

[9] This portfolio loan encumbers 10 properties (Savannah I, Savannah II, Columbia, Lexington I, Stuart I, Lexington II, Stuart II, Bluffton, Wilmington Island and Myrtle Beach). The net book value of the encumbered properties as of December 31, 2013 was approximately $34.5 million. Such amounts are only available to satisfy the obligations of this loan.

[10] This portfolio loan encumbers nine properties (Los Angeles - La Cienega, Las Vegas III, Las Vegas VI, Hampton, SF Bay Area - Gilroy, Toms River, Crescent Springs, Florence and Walton). The net book value of the encumbered properties as of December 31, 2013 was approximately $42.6 million. Such amounts are only available to satisfy the obligations of this loan.

[11] This portfolio loan encumbers six properties (Mt. Pleasant I, Charleston I, Charleston II, Mt. Pleasant II, Charleston III, and Mt. Pleasant III). The net book value of the encumbered properties as of December 31, 2013 was approximately $37.2 million. Such amounts are only available to satisfy the obligations of this loan.

[12] Through October 28, 2013, this loan was collateralized by the Homeland Portfolio (Kennesaw, Sharpsburg, Duluth I, Duluth II, Duluth III, Marietta III, Austell, Sandy Springs, Smyrna, Lawrenceville II, Jacksonville I and Jacksonville II). This loan was a variable rate loan, such rate was based on 30-day LIBOR, which including the applicable spread equaled an interest rate of 4.67% as of October 28, 2013; however, we were required to purchase an interest rate swap with a notional amount of $45 million, and, inclusive of the interest rate swap, the effective fixed interest rate was 5.41%. For additional discussion, see "Second Restated KeyBank Loan" below. This loan was paid off in October 2013 in connection with entering into a revolving loan agreement with KeyBank National Association (the "KeyBank Revolver"). The KeyBank Revolver is further described below.

[13] On October 28, 2013, through our Operating Partnership and certain property-owning special purpose entities wholly-owned by our Operating Partnership, we entered into the KeyBank Revolver, which matures on October 25, 2016. Such loan encumbers the Homeland Portfolio properties, the Knoxville Portfolio properties and five other previously unencumbered properties (Gulf Breeze II, El Paso I, Toms River II, North Charleston and Phoenix I). This loan is a LIBOR based variable rate loan, and such rate is based on 30-day LIBOR, which including the applicable spread equaled an initial interest rate of 1.67% as of October 28, 2013 and remained at such interest rate as of December 31, 2013. The interest rate swap with a notional amount of $45 million that was originally entered into in connection with the Second Restated KeyBank Loan remains outstanding; inclusive of the interest rate swap, the effective fixed interest rate as of December 31, 2013 was approximately 2.4%. For additional discussion, see "KeyBank Revolver" below.