Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives Fair Value	$ 6,774
Current maturities on long-term debt	23,707	$ 38,707
Total long-term debt, net	1,489,289	1,503,609
Liability Derivatives Fair Value		8,455
Other Assets [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives Fair Value	$ 6,800
Other Liabilities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Liability Derivatives Fair Value		$ 8,500