Schedule - Summary of Changes in Total Real Estate and Accumulated Depreciation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III, Real Estate Accumulated Depreciation, Held For Sale				$ 65,426		$ 50,457
SEC Schedule III, Real Estate, Gross, Held for Sale				184,134		159,387
SEC Schedule III, Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, beginning of year	$ 3,285,404	$ 3,527,868	$ 3,477,540
Improvements and development	69,486	103,946	79,345
Acquisitions	476,516	20,227	59,078
Impairment of assets	(195,111)	(33,536)	(37,708)
Dispositions	(71,172)	(331,480)	(45,047)
Write-off of fully depreciated assets	(13,100)	(1,621)	(5,340)
Reclassification to held for sale	(184,134)	0	0	(184,134)	$ 0	0
Balance, end of year	3,367,889	3,285,404	3,527,868
Balance, end of year – held for sale	(184,134)	0	0
SEC Schedule III, Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, beginning of year	1,061,051	1,012,746	907,928
Depreciation expense	131,102	133,699	132,114
Impairment of assets	(60,461)	(13,841)	(7,742)
Dispositions	(37,519)	(69,933)	(14,214)
Write-off of fully depreciated assets	(13,100)	(1,620)	(5,340)
Reclassification to held for sale				(65,426)	0	0
Balance, end of year	$ 1,015,647	$ 1,061,051	$ 1,012,746
Balance, end of year – held for sale				$ (65,426)	$ 0	$ 0