Schedule - Summary of Changes in Total Real Estate and Accumulated Depreciation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III, Real Estate Accumulated Depreciation, Held For Sale			$ 0	$ 0	$ 26,574
SEC Schedule III, Real Estate, Gross, Held for Sale			184,134	0	70,808
SEC Schedule III, Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance, beginning of year	$ 3,300,014	$ 3,367,889	3,285,404
Improvements and development	502,077	116,575	69,486
Acquisitions	2,613	27,234	476,516
Impairment of assets	(89,101)	(74,391)	(195,111)
Dispositions	(402,783)	(61,360)	(71,172)
Write-off of fully depreciated assets	(13,118)	(5,125)	(13,100)
Reclassification to held for sale	0	(70,808)		0	(70,808)	$ (184,134)
Balance, end of year	3,299,702	3,300,014	3,367,889
Balance, end of year – held for sale	0	(70,808)
SEC Schedule III, Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance, beginning of year	1,060,845	1,015,647	1,061,051
Depreciation expense	118,485	124,433	131,102
Impairment of assets	(39,264)	(35,998)	(60,461)
Dispositions	(15,941)	(11,538)	(37,519)
Write-off of fully depreciated assets	(13,118)	(5,125)	(13,100)
Reclassification to held for sale				0	(26,574)	(65,426)
Balance, end of year	$ 1,111,007	$ 1,060,845	$ 1,015,647
Balance, end of year – held for sale				$ 0	$ (26,574)	$ (65,426)