Schedule of Debt Outstanding (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 1,778,684	$ 1,459,000
Unamortized debt issuance costs	(13,704)	(11,813)
Current portion of long-term debt	(12,795)	(10,000)
Long-term debt, net	1,752,185	1,437,187
Term Loan Due in April 2023
Debt Instrument [Line Items]
Total debt	198,750	85,000
Unamortized debt issuance costs	(100)	(300)
Senior Notes 4.625% Due 2023
Debt Instrument [Line Items]
Total debt	350,000	350,000
Unamortized debt issuance costs	(2,900)	(3,300)
Senior Notes 4.125% Due 2020
Debt Instrument [Line Items]
Total debt	325,000	325,000
Unamortized debt issuance costs	(1,300)	(1,900)
Senior Notes 5.0% Due 2022
Debt Instrument [Line Items]
Total debt	250,000	250,000
Unamortized debt issuance costs	(1,900)	(2,300)
Senior Notes 4.75% Due 2027
Debt Instrument [Line Items]
Total debt	250,000	250,000
Unamortized debt issuance costs	(3,600)	(4,000)
Non-Recourse Mortgage Note 4.5% Due 2033
Debt Instrument [Line Items]
Total debt	23,725
Unamortized debt issuance costs	(300)
Non-Recourse Mortgage Note 4.43% Due 2040
Debt Instrument [Line Items]
Total debt	35,363
Unamortized debt issuance costs	(3,400)
Non-Recourse Mortgage Note 4.5% Due 2034
Debt Instrument [Line Items]
Total debt	156,846
Unamortized debt issuance costs	(200)
Revolving Credit Facility | Revolving Credit Facility Due in April 2023
Debt Instrument [Line Items]
Total debt	$ 189,000	$ 199,000