Debt - Long-Term Debt Maturities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
2018	$ 168,894
2019	447,337
2020	1,498,040
2021 (3)	907,610
2022	1,295,191
Thereafter	5,152,034
Subtotal	9,469,106
Premiums (discounts), net	(16,673)
Debt issuance costs, net	(39,802)
Total	9,412,631	$ 10,608,294
Credit Facilities [Member]
Debt Instrument [Line Items]
2018	0
2019	0
2020	264,982
2021 (3)	52,410
2022	0
Thereafter	0
Subtotal	317,392
Premiums (discounts), net	0
Debt issuance costs, net	0
Total	317,392	35,023
Senior Notes [Member]
Debt Instrument [Line Items]
2018	0
2019	0
2020	719,580
2021 (3)	839,510
2022	839,510
Thereafter	3,715,027
Subtotal	6,113,627
Premiums (discounts), net	(21,333)
Debt issuance costs, net	(25,017)
Total	6,067,277	6,417,492
Term Loans And Other Debt [Member]
Debt Instrument [Line Items]
2018	934
2019	1,013
2020	501,077
2021 (3)	910
2022	444,890
Thereafter	1,122,709
Subtotal	2,071,533
Premiums (discounts), net	0
Debt issuance costs, net	(11,042)
Total	2,060,491	$ 1,499,001
Secured Mortgage Debt [Member]
Debt Instrument [Line Items]
2018	167,960
2019	446,324
2020	12,401
2021 (3)	14,780
2022	10,791
Thereafter	314,298
Subtotal	966,554
Premiums (discounts), net	4,660
Debt issuance costs, net	(3,743)
Total	$ 967,471