• Filing Date: 2018-03-07
  • Form Type: 10-K
  • Description: Annual report
v3.8.0.1
Fair Value Measurements - Components of Long-Term Debt and Methods Used in Estimating Fair Values (Parenthetical) (Detail)
Dec. 31, 2017
Apr. 03, 2017
Mar. 03, 2017
Feb. 27, 2017
Aug. 16, 2016
Jan. 14, 2016
Senior Notes [Member]            
Debt Instrument [Line Items]            
Fixed annual rate of interest 8.00% 8.00%        
3.875% Convertible Senior Notes [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 3.875%          
4.25% Convertible Senior Notes [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 4.25% 4.25% 4.25%      
3.95% Promissory Note [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 3.95%     3.95%    
4% Promissory Note [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 4.00%         4.00%
3.75% Promissory Note [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 3.75%       3.75%