Notes Payable - Summary of Notes Payable (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Notes payable	$ 212,918,000		$ 192,491,000
Fixed Rate Debt | RIF V - Jersey, LLC
Debt Instrument [Line Items]
Notes payable	5,145,000	[1]	5,189,000	[1]
Maturity Date	Jan. 01, 2015
Fixed interest rate	5.45%	[2]
Fixed Rate Debt | The Park
Debt Instrument [Line Items]
Notes payable	3,148,000	[3]	3,177,000	[3]
Maturity Date	Jan. 03, 2031
Fixed interest rate	5.13%	[4]
Variable Rate Debt | Term Loan
Debt Instrument [Line Items]
Notes payable	60,000,000	[5]	60,000,000	[5]
Maturity Date	Aug. 01, 2019	[5]
Variable interest rate	LIBOR + 1.90%	[5]
Variable Rate Debt | RIF V - Glendale Commerce Center, LLC
Debt Instrument [Line Items]
Notes payable	42,750,000		42,750,000
Maturity Date	May 01, 2016	[6]
Variable interest rate	LIBOR + 2.00%
Revolving Credit Facility | Unsecured Credit Facility
Debt Instrument [Line Items]
Notes payable	$ 101,875,000		$ 81,375,000
Maturity Date	Jul. 24, 2016	[6]
Variable interest rate	LIBOR + 1.50%	[7]

[1] Includes unamortized debt premium of $38,000 at March 31, 2014 and $50,000 at December 31, 2013.

[2] Monthly payments of interest and principal based on 30-year amortization table.

[3] Includes unamortized debt discount of $117,000 at March 31, 2014 and $118,000 at December 31, 2013.

[4] Monthly payments of interest and principal based on 20-year amortization table.

[5] Loan is secured by six properties and has one additional one year extension available.

[6] Two additional one year extensions available at the borrower’s option.

[7] The facility additionally bears interest at 0.30% or 0.20% of the daily unused commitment, if the balance is under $100 million or over $100 million, respectively. The daily unused commitment is calculated as $200 million less the daily outstanding balance.