Debt - Long-Term Debt Maturities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2016	$ 21,000
2017	1,044,000
2018	746,000
2019	1,081,000
2020	1,189,000
2021	1,818,000
2022	1,573,000
2023	1,313,000
2024	911,000
2025	891,000
Thereafter	564,000
Subtotal	11,151,000
Unamortized premiums (discounts), net	38,000
Unamortized debt issuance costs, net	(50,000)
Totals	11,139,415	$ 11,626,831
Credit Facilities [Member]
Debt Instrument [Line Items]
Totals	0	0
Senior Notes [Member]
Debt Instrument [Line Items]
Totals	6,603,070	6,516,392
Secured Mortgage Debt [Member]
Debt Instrument [Line Items]
Totals	901,071	$ 1,172,473
Wholly Owned
Debt Instrument [Line Items]
2016	15,000
2017	530,000
2018	343,000
2019	938,000
2020	937,000
2021	1,690,000
2022	1,419,000
2023	1,171,000
2024	910,000
2025	890,000
Thereafter	562,000
Subtotal	9,405,000
Unamortized premiums (discounts), net	(11,000)
Unamortized debt issuance costs, net	(45,000)
Totals	9,349,000
Wholly Owned | Credit Facilities [Member]
Debt Instrument [Line Items]
2016	0
2017	0
2018	0
2019	0
2020	0
2021	0
2022	0
2023	0
2024	0
2025	0
Thereafter	0
Subtotal	0
Unamortized premiums (discounts), net	0
Unamortized debt issuance costs, net	0
Totals	0
Wholly Owned | Senior Notes [Member]
Debt Instrument [Line Items]
2016	0
2017	0
2018	175,000
2019	618,000
2020	877,000
2021	1,277,000
2022	777,000
2023	850,000
2024	777,000
2025	750,000
Thereafter	555,000
Subtotal	6,656,000
Unamortized premiums (discounts), net	(22,000)
Unamortized debt issuance costs, net	(31,000)
Totals	6,603,000
Wholly Owned | Term Loans And Other Debt [Member]
Debt Instrument [Line Items]
2016	1,000
2017	522,000
2018	1,000
2019	1,000
2020	1,000
2021	399,000
2022	632,000
2023	288,000
2024	1,000
2025	1,000
Thereafter	7,000
Subtotal	1,854,000
Unamortized premiums (discounts), net	0
Unamortized debt issuance costs, net	(9,000)
Totals	1,845,000
Wholly Owned | Secured Mortgage Debt [Member]
Debt Instrument [Line Items]
2016	14,000
2017	8,000
2018	167,000
2019	319,000
2020	59,000
2021	14,000
2022	10,000
2023	33,000
2024	132,000
2025	139,000
Thereafter	0
Subtotal	895,000
Unamortized premiums (discounts), net	11,000
Unamortized debt issuance costs, net	(5,000)
Totals	901,000
Consolidated Entities
Debt Instrument [Line Items]
2016	6,000
2017	514,000
2018	403,000
2019	143,000
2020	252,000
2021	128,000
2022	154,000
2023	142,000
2024	1,000
2025	1,000
Thereafter	2,000
Subtotal	1,746,000
Unamortized premiums (discounts), net	49,000
Unamortized debt issuance costs, net	(5,000)
Totals	$ 1,790,000