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Summary of Significant Accounting Policies - Additional Information 3 (Detail) - USD ($)
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Operations And Summary Of Significant Accounting Policies [Line Items]      
Federal statutory rate 21.00% 35.00%  
Operating losses carryforward indefinitely with no carryback as percentage of taxable income 80.00%    
Interest expense threshold percentage of adjusted taxable income beyond which interest expense is deductible 30.00%    
Deferred federal tax, Remeasurement Rate 21.00%    
Deferred federal tax, Remeasurement Value $ 140,400,000    
Refundable unused AMT credit carryforward, Percentage 50.00%    
Refundable unused alternative minimum tax credit carryforward years 2018 through 2020    
Refundable unused AMT credit carryforward, Valuation Allowance     $ 19,100,000
Refundable unused AMT credit carryforward, year fully refunded by 2021    
Cumulative common stock ownership change over three year period that would limit federal and state net operating loss carry forwards 50.00%    
Derivative financial instruments, asset $ 2,500,000   $ 1,300,000
Fixed Rate Debt      
Operations And Summary Of Significant Accounting Policies [Line Items]      
Long-term debt, including current portion, Carrying Value 1,100,000,000    
Level 2 | Fixed Rate Debt      
Operations And Summary Of Significant Accounting Policies [Line Items]      
Long-term debt, including current portion, Fair Value 1,200,000,000    
Fair Value, Measurements, Recurring | Level 3      
Operations And Summary Of Significant Accounting Policies [Line Items]      
Financial assets 0    
Financial liabilities $ 0