Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Legal Matters (Details)

v3.8.0.1
Commitments and Contingencies - Legal Matters (Details) - USD ($)
$ / shares in Units, $ in Millions
1 Months Ended 12 Months Ended
Mar. 31, 2017
Aug. 31, 2016
Aug. 31, 2014
Dec. 31, 2016
Dec. 31, 2017
Sep. 30, 2017
UMG Recordings | Settled Litigation            
Loss Contingencies [Line Items]            
Payments for legal settlements $ 5.0 $ 18.0        
Issuance of common stock for legal settlements (in shares)   1,800,000        
SwiftAir, LLC | Pending Litigation            
Loss Contingencies [Line Items]            
Damages sought     9.0      
Common Stock            
Loss Contingencies [Line Items]            
Issuance of common stock for legal settlements (in shares)       1,751,000    
Common Stock | UMG Recordings            
Loss Contingencies [Line Items]            
Shares issued in period (in shares)   1,800,000        
Price Per Share Scenario One | Common Stock | UMG Recordings            
Loss Contingencies [Line Items]            
Shares issued in period (in shares) 500,000 500,000.0        
Share Price (in usd per share) $ 10.00 $ 10     $ 10 $ 10.00
Price Per Share Scenario Two | Common Stock | UMG Recordings            
Loss Contingencies [Line Items]            
Shares issued in period (in shares) 400,000 400,000.0        
Share Price (in usd per share) $ 12.00 $ 12     $ 12 $ 12.00