Other Long-Term Assets - Narrative (Details) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2016
Debt Instrument [Line Items]      
Proceeds from sale of life insurance policies $ 11,902,000 $ 21,338,000  
Convertible Senior Notes at 5.00% February 2021 [Member] | Convertible Subordinated Debt      
Debt Instrument [Line Items]      
Debt Instrument, Face Amount     $ 150,000,000