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Debt - Additional Information (Detail)
 3 Months Ended 12 Months Ended
Oct. 05, 2017
USD ($)
Apr. 17, 2017
USD ($)
Jun. 30, 2017
USD ($)
Dec. 31, 2017
USD ($)
$ / shares
Dec. 31, 2016
USD ($)
shares
$ / shares
Dec. 31, 2015
USD ($)
May 08, 2017
Debt Instrument [Line Items]              
Cash paid for interest       $ 39,900,000 $ 22,100,000 $ 14,400,000  
Capitalized interest expense       4,200,000 3,000,000 3,100,000  
Charge recognized as a result of redemption       1,500,000 4,000,000 0  
Payments for capped call transactions       0 27,300,000 $ 0  
Convertible Senior Notes 2021              
Debt Instrument [Line Items]              
Aggregate principal amount         1,000    
Credit Agreement | Revolving Credit Facility              
Debt Instrument [Line Items]              
Maximum borrowing capacity $ 125,000,000            
Accordion feature increase limit $ 150,000,000            
Borrowings outstanding       0      
Availability under the facility, net of letters of credit issued       110,500,000      
Springing maturity, period prior to maturity date of convertible senior notes due 2021 91 days            
Springing maturity, period prior to maturity date of secured notes due 2022 60 days            
Credit Agreement | Letters of Credit              
Debt Instrument [Line Items]              
Maximum borrowing capacity       30,000,000.0      
Letters of credit outstanding       $ 4,700,000      
Senior Notes | Senior Secured Notes Due 2022              
Debt Instrument [Line Items]              
Aggregate principal amount   $ 440,000,000          
Interest rate   10.75%          
Redemption price, percent of principal amount of notes redeemed       100.00%      
Percent of notes with option to redeem       35.00%      
Redemption price, percentage of principal amount   110.75%          
Redemption price if required collateral coverage ratio not met, percentage of principal amount   100.00%          
Minimum collateral coverage ratio   1.50          
Collateral coverage ratio, amount added to cash and cash equivalents   4.75          
Collateral coverage ratio, multiplier for Average Grantor EBITDA for seven most recent fiscal quarters   4          
Period to redeem notes without default if required collateral coverage ratio not met   90 days          
Redemption price if company experiences change of control, percent of principal amount   101.00%          
Senior Notes | 6.25% senior notes              
Debt Instrument [Line Items]              
Interest rate       6.25%     6.25%
Charge recognized as a result of redemption     $ 1,500,000        
Premium and expenses paid for redemption of debt     1,300,000        
Write off of unamortized discount and fees related to the portion of the notes redeemed     $ 200,000        
Senior Notes | Convertible Senior Notes 2021              
Debt Instrument [Line Items]              
Aggregate principal amount       $ 213,500,000.0 $ 213,500,000.0    
Interest rate       5.50% 5.50%    
Effective interest rate         9.50%    
Conversion rate (in shares) | shares         102.4249    
Total amount of conversion (in shares) | shares         21,867,716    
Conversion price (in usd per share) | $ / shares       $ 12.75 $ 9.76    
Payments for capped call transactions         $ 27,300,000    
Conversion premium       60.00% 22.50%    
Line of Credit | Credit Agreement | Revolving Credit Facility              
Debt Instrument [Line Items]              
Requirement to maintain fixed charge coverage ratio, availability threshold, percent of lender commitments under facility 10.00%            
Requirement to maintain fixed charge coverage ratio, availability threshold $ 15,000,000            
Amount of aggregate default under other debt that would trigger event of default $ 50,000,000