Stockholders’ Equity of the Company and Partners' Capital of the Operating Partnership - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Class of Stock [Line Items]
Conversion of Units / Limited Partner Units to Common Stock / General Partner Units	$ 0	$ 0
Common stock dividends and Unit distributions	$ 44,283
Convertible Common Stock
Class of Stock [Line Items]
Conversion of Units to Common Stock	11,012	175,333
Conversion of Units / Limited Partner Units to Common Stock / General Partner Units	$ 106	$ 1,697
Common Stock and Operating Partnership Units
Class of Stock [Line Items]
Common stock dividends and Unit distributions	$ 44,283