Property Dispositions and Real Estate Impairment - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Property	Dec. 31, 2016 USD ($) Property	Dec. 31, 2015 USD ($) Property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of property	$ 223,853	$ 370,038	$ 156,461
Aggregate gain on sale of properties	63,428	81,510	24,884
Gain (loss) on debt extinguishment on sale of properties	$ 5,938	$ (532)	21,498
Properties classified as held-for-sale (in number of properties) | Property	1	2
Other asset impairment charges	$ 39,702	$ 100,195	36,832
LCIF [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of property	17,847	238,891
Aggregate gain on sale of properties	4,491	36,380	0
Impairment charges on real estate	$ 5,259	72,072	$ 787
Number of properties sold | Property			0
Gain (loss) on debt extinguishment on sale of properties		$ 7,388
Properties classified as held-for-sale (in number of properties) | Property	0	0
Land [Member] | New York, New York [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges on real estate		$ 65,500
Number of properties sold | Property		3
Land [Member] | New York, New York [Member] | LCIF [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges on real estate		$ 65,500
Number of properties sold | Property		3
Office Building [Member] | LCIF [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment charges	$ 6,802