Real Estate Activities (Investments in Real Estate) (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Real Estate [Abstract]
Buildings, improvements and construction in progress	$ 2,847,986	$ 2,843,326
Land, including land held for development	519,903	442,078
Total investments in real estate	3,367,889	3,285,404
Accumulated depreciation	(1,015,647)	(1,061,051)
Net investments in real estate	$ 2,352,242	$ 2,224,353