• Filing Date: 2018-03-07
  • Form Type: 10-K
  • Description: Annual report
v3.8.0.1
Long-Term Debt - Summary of Long-Term Debt (Parenthetical) (Detail)
12 Months Ended
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%        
Debt instrument, repurchase date Apr. 03, 2017          
3.875% Convertible Senior Notes [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 3.875%          
Debt instrument, maturity date Mar. 15, 2019          
4.25% Convertible Senior Notes [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 4.25% 4.25% 4.25%      
Debt instrument, maturity date Mar. 01, 2037          
3.95% Promissory Note [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 3.95%     3.95%    
Debt instrument, maturity date Feb. 17, 2020          
4% Promissory Note [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 4.00%         4.00%
Debt instrument, maturity date Feb. 01, 2031          
3.75% Promissory Note [Member]            
Debt Instrument [Line Items]            
Debt instrument stated interest rate 3.75%       3.75%  
Debt instrument, maturity date Sep. 01, 2036