Acquired Lease Intangibles - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
In-place Lease Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	$ 1.3	$ 0.8
Below-market Lease Liabilities [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	0.2	0.1
Below-market Ground Lease Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	$ 0.1	$ 0.1