Annual report pursuant to Section 13 and 15(d)

Long Term Debt (Searchlight Note) (Details)

v3.8.0.1
Long Term Debt (Searchlight Note) (Details)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Feb. 02, 2015
USD ($)
$ / shares
shares
Debt Instrument [Line Items]      
Unamortized discount $ 19,466,000 $ 21,878,000  
Accrued interest to stock appreciation right rate 0.04    
Stock Appreciation Rights (SARs) | Class A-1 Common Stock      
Debt Instrument [Line Items]      
Stock appreciation rights (in shares) | shares     3,000,000
Exercise price of rights (USD per share) | $ / shares     $ 13.00
Searchlight Promissory Note | Unsecured Debt      
Debt Instrument [Line Items]      
Face amount of debt     $ 75,000,000
Unamortized discount     $ 21,700,000
Searchlight Promissory Note | Stock Appreciation Rights (SARs) | Class A-1 Common Stock      
Debt Instrument [Line Items]      
Stock appreciation rights (in shares) | shares     3,000,000
Exercise price of rights (USD per share) | $ / shares     $ 13.00