Schedule III-Real Estate and Accumulated Depreciation (Summary of Transactions in Real Estate and Accumulated Depreciation) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate
Beginning Balance	$ 786,244	$ 1,138,108	$ 2,142,067
Acquisitions	100,687		169,417
Dispositions and assets held for sale	(88,461)	(271,464)	(1,108,581)
Impairment provision		(80,400)	(64,795)
Ending Balance	798,470	786,244	1,138,108
Accumulated Depreciation
Beginning Balance	(255,883)	(279,541)	(415,216)
Depreciation	(29,282)	(36,866)	(64,652)
Accumulated depreciation on dispositions and assets held for sale		60,524	200,327
Ending Balance	$ (285,165)	$ (255,883)	$ (279,541)