Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability Derivatives Fair Value	$ 8,455	$ 22,808
Current maturities on long-term debt	38,707	51,713
Total long-term debt, net	1,503,609	1,531,069
Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability Derivatives Fair Value	$ 8,455	$ 22,808