Goodwill and Other Intangibles (Details (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Intangible assets      
Goodwill, Period Increase (Decrease) $ 0   $ 0
Gross Carrying Amount 62,500,000   62,500,000
Accumulated Amortization (22,100,000)   (19,500,000)
Net Carrying Amount 40,400,000   43,000,000
Amortization of intangible assets 2,600,000 2,500,000  
Technology      
Intangible assets      
Gross Carrying Amount 27,200,000   27,200,000
Accumulated Amortization (12,100,000)   (10,600,000)
Net Carrying Amount 15,100,000   16,600,000
Technology | Minimum      
Intangible assets      
Useful Life (in years) 3 years    
Technology | Maximum      
Intangible assets      
Useful Life (in years) 5 years    
Customer Relationships      
Intangible assets      
Gross Carrying Amount 27,000,000   27,000,000
Accumulated Amortization (4,000,000)   (3,400,000)
Net Carrying Amount 23,000,000   23,600,000
Customer Relationships | Minimum      
Intangible assets      
Useful Life (in years) 10 years    
Customer Relationships | Maximum      
Intangible assets      
Useful Life (in years) 12 years    
Trademarks      
Intangible assets      
Useful Life (in years) 3 years    
Gross Carrying Amount 5,600,000   5,600,000
Accumulated Amortization (3,800,000)   (3,400,000)
Net Carrying Amount 1,800,000   2,200,000
FCC licenses and other      
Intangible assets      
Gross Carrying Amount 2,700,000   2,700,000
Accumulated Amortization (2,200,000)   (2,100,000)
Net Carrying Amount $ 500,000   $ 600,000
FCC licenses and other | Minimum      
Intangible assets      
Useful Life (in years) 2 years    
FCC licenses and other | Maximum      
Intangible assets      
Useful Life (in years) 20 years