Property Acquisitions - Pro Forma Condensed Financial Information (Detail) - Proforma Financial Information for Acquisition Properties [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Business Acquisition Pro Forma Information [Line Items]
Revenues from continuing operations	$ 29,987	$ 88,389
Earnings from continuing operations	$ 8,523	$ 21,820
Basic and diluted earnings from continuing operations per common share	$ 0.25	$ 0.64