Debt - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended			9 Months Ended		0 Months Ended			0 Months Ended		0 Months Ended
	Sep. 30, 2014	Dec. 31, 2013 Agreement	Aug. 01, 2014	Dec. 31, 2013 Non-Recourse Secured Financing [Member]	Sep. 30, 2014 B Note [Member] Cerritos, CA [Member]	Dec. 31, 2013 B Note [Member] Cerritos, CA [Member]	Oct. 15, 2012 Notes Payable, Other Payables [Member] 5400 Westheimer LP [Member]	Sep. 30, 2014 Notes Payable, Other Payables [Member] 5400 Westheimer LP [Member]	Dec. 31, 2013 Notes Payable, Other Payables [Member] Cerritos, CA [Member] 5400 Westheimer LP [Member]	Sep. 10, 2014 Unsecured Working Capital Loan [Member] KeyBank National Association [Member]	Sep. 10, 2014 Unsecured Working Capital Loan [Member] KeyBank National Association [Member]	Sep. 10, 2014 Unsecured Working Capital Loan [Member] KeyBank National Association [Member] London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Mortgage loans payable	$ 375,335,000	$ 444,933,000
Secured financing aggregate amount		29,150,000	1,699,000	29,150,000
Number of financing arrangements		2
Loan from KeyBank National Association											25,000,000
Debt instrument, variable interest rate												3.00%
Debt instrument, maturity date	Aug. 15, 2022						Oct. 15, 2022			Mar. 10, 2015
Early repayment month and year										2014-10
Note issued					14,500,000		1,600,000
Interest rate of B Note					6.6996%		15.00%
Amount payable on notes for interest accruing					12,000		800,000
Percentage on return on capital					9.00%		50.00%
Liquidation value of loan					0
Carrying value of loan						$ 942,000		$ 800,000	$ 800,000