• Filing Date: 2018-03-07
  • Form Type: 10-K
  • Description: Annual report
v3.8.0.1
Fair Value Measurements - Schedule of Fair Value Information for Financial Assets and Liabilities Carried on Balance Sheet (Detail) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Financial Assets:    
Limited partnership investments $ 23,184 $ 29,263
Financial Liabilities:    
Total long-term debt 237,835 138,863
Estimate of Fair Value Measurement [Member]    
Financial Assets:    
Limited partnership investments 23,184 29,263
Financial Liabilities:    
Total long-term debt 240,212 143,484
Revolving credit facility   9,463
Estimate of Fair Value Measurement [Member] | Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt   41,618
Estimate of Fair Value Measurement [Member] | 3.875% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt 90,827 84,696
Estimate of Fair Value Measurement [Member] | 4% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 7,820 8,664
Estimate of Fair Value Measurement [Member] | 3.75% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 9,227 8,506
Estimate of Fair Value Measurement [Member] | 4.25% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt 124,444  
Estimate of Fair Value Measurement [Member] | 3.95% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 7,894  
Estimate of Fair Value Measurement [Member] | (Level 2) [Member]    
Financial Liabilities:    
Total long-term debt 215,271 41,618
Estimate of Fair Value Measurement [Member] | (Level 2) [Member] | Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt   41,618
Estimate of Fair Value Measurement [Member] | (Level 2) [Member] | 3.875% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt 90,827  
Estimate of Fair Value Measurement [Member] | (Level 2) [Member] | 4.25% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt 124,444  
Estimate of Fair Value Measurement [Member] | (Level 3) [Member]    
Financial Assets:    
Limited partnership investments 23,184 29,263
Financial Liabilities:    
Total long-term debt 24,941 101,866
Revolving credit facility   9,463
Estimate of Fair Value Measurement [Member] | (Level 3) [Member] | 3.875% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt   84,696
Estimate of Fair Value Measurement [Member] | (Level 3) [Member] | 4% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 7,820 8,664
Estimate of Fair Value Measurement [Member] | (Level 3) [Member] | 3.75% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 9,227 8,506
Estimate of Fair Value Measurement [Member] | (Level 3) [Member] | 3.95% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 7,894  
Carrying Value [Member]    
Financial Assets:    
Limited partnership investments 23,184 29,263
Financial Liabilities:    
Total long-term debt 237,835 138,863
Revolving credit facility   9,463
Carrying Value [Member] | Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt   39,448
Carrying Value [Member] | 3.875% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt 85,436 81,988
Carrying Value [Member] | 4% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 8,206 8,660
Carrying Value [Member] | 3.75% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt 8,469 $ 8,767
Carrying Value [Member] | 4.25% Convertible Senior Notes [Member]    
Financial Liabilities:    
Total long-term debt 126,454  
Carrying Value [Member] | 3.95% Promissory Note [Member]    
Financial Liabilities:    
Total long-term debt $ 9,270