Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended	12 Months Ended							0 Months Ended	12 Months Ended	0 Months Ended
	Sep. 22, 2011	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 SF Bay Area - San Lorenzo	Dec. 31, 2013 Common Stock	Dec. 31, 2012 Common Stock	Dec. 31, 2011 Common Stock	Sep. 28, 2013 Distribution Reinvestment Plan	Dec. 31, 2013 Distribution Reinvestment Plan	Sep. 28, 2013 Distribution Reinvestment Plan Maximum	Sep. 23, 2013 Distribution Reinvestment Plan Maximum
Commitments and Contingencies [Line Items]
Previous purchase price per share											$ 9.50
Previous purchase price percentage of fair market value of a share											95.00%
Percentage of offering price under distribution reinvestment plan											95.00%
Current purchase price per share											$ 10.25
Amendment, suspension or termination period of share										10 days
Additional shares registered			$ 15,796,431	$ 12,311,983	$ 9,045,444		$ 1,541	$ 1,235	$ 952		$ 4,400,000	$ 51,250,000	$ 51,250,000
Plan effective date											Sep. 28, 2013
Shares issued pursuant to distribution reinvestment plan	10,000,000						1,540,890	1,235,628	952,152		400,000
Redemptions of common stock (in shares)							1,473,355	1,310,527	993,301
Redemption of common stock			14,366,834	12,577,236	9,680,138		1,474	1,311	993
Common stock, redeemed shares, per share			$ 9.75	$ 9.60	$ 9.75
Unregistered shares sold			3,900,000
Investors holding amount rescinded		10,000
Investors holding shares rescission		1,000
Minimum return required on property contributed for class D unit holders to modify exchange rights			$ 0.70
Limited partnership unit, conversion description			The limited partners of our Operating Partnership have the right to cause our Operating Partnership to redeem their limited partnership units for cash equal to the value of an equivalent number of our shares, or, at our option, we may purchase their limited partnership units by issuing one share of our common stock for each limited partnership unit redeemed.
Remaining term of lease						21 years
Rent expense						147,000
Minimum lease payment 2014						133,000
Minimum lease payment 2015						139,000
Minimum lease payment 2016						139,000
Minimum lease payment 2017						139,000
Minimum lease payment 2018						$ 139,000