Schedule III- Summary of Changes in Total Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]
Balance, beginning of year	$ 3,184,594	$ 3,299,702	$ 3,300,014
Improvements and development	137,593	125,616	502,077
Acquisitions	0	21,250	2,613
Impairment of assets	(3,989)	(201,818)	(89,101)
Dispositions	(81,118)	(4,856)	(402,783)
Write-off of fully depreciated assets	(12,031)	(32,993)	(13,118)
Reclassification to held for sale	(14,123)	(22,307)	0
Balance, end of year	3,210,926	3,184,594	3,299,702
Balance, end of year – held for sale	15,653	22,307	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward]
Balance, beginning of year	1,118,582	1,111,007	1,060,845
Depreciation expense	125,495	120,718	118,485
Impairment of assets	(484)	(75,586)	(39,264)
Dispositions	(25,693)	(4,564)	(15,941)
Write-off of fully depreciated assets	(12,031)	(32,993)	(13,118)
Reclassification to held for sale	(3,147)	0	0
Balance, end of year	1,202,722	1,118,582	1,111,007
Balance, end of year – held for sale	$ 3,147	$ 0	$ 0