Other Long-Term Obligations - Narrative (Details) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Apr. 23, 2015
Income Tax Examination [Line Items]      
Deferred gain on sale leaseback $ 6,703,000 $ 6,978,000 $ 7,414,000
Sale Leaseback Transaction, Current Period Gain Recognized 265,000 $ 171,000  
Convertible Subordinated Debt | Convertible Senior Notes at 5.00% February 2021 [Member]      
Income Tax Examination [Line Items]      
Debt Instrument, Face Amount $ 150,000,000    
Interest rate (as a percent) 5.00%