Fair Value Measurements - Summary of the Face Values, Carrying Amounts and Fair Values of Company's Financial Instruments Using Level 2 Inputs, for Senior Unsecured Notes Payable, and Level 3 Inputs, for all Other Financial Instruments (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financial assets:
Preferred equity investment - face value	$ 12,031,000	$ 7,500,000
Preferred equity investment	13,900,000
Financial liabilities:
Senior unsecured notes payable, net	255,294,000	254,229,000
Mortgage notes payable, net	$ 0	94,676,000
Fair value measurement, description	the Company measures fair value using (i) a valuation technique that uses the quoted price of the identical liability when traded as an asset or quoted prices for similar liabilities when traded as assets or (ii) another valuation technique that is consistent with the principles of fair value measurement, such as the income approach or the market approach.
Level 2 [Member] | Senior unsecured notes payable [Member]
Financial liabilities:
Financial liabilities - face value	$ 260,000,000	260,000,000
Level 3 [Member] | Mortgage notes payable [Member]
Financial liabilities:
Financial liabilities - face value	0	95,022,000
Carrying Amount [Member]
Financial assets:
Preferred equity investment	13,872,000	8,477,000
Carrying Amount [Member] | Level 2 [Member]
Financial liabilities:
Senior unsecured notes payable, net	255,294,000	254,229,000
Carrying Amount [Member] | Level 3 [Member]
Financial liabilities:
Mortgage notes payable, net	0	94,676,000
Fair Value [Member]
Financial assets:
Preferred equity investment	14,289,000	8,477,000
Fair Value [Member] | Level 2 [Member]
Financial liabilities:
Senior unsecured notes payable, net	265,850,000	263,575,000
Fair Value [Member] | Level 3 [Member]
Financial liabilities:
Mortgage notes payable, net	$ 0	$ 97,067,000