Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v2.4.0.8
Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 9 Months Ended
Sep. 30, 2014
Sep. 30, 2013
Sep. 30, 2014
Unit
Segment
Sep. 30, 2013
Dec. 31, 2013
Unit
Sep. 30, 2014
Minimum
Sep. 30, 2014
Maximum
Sep. 30, 2014
Leasehold Improvements
Sep. 30, 2014
Other Fixed Assets
Minimum
Sep. 30, 2014
Other Fixed Assets
Maximum
Sep. 30, 2014
Equity Method Investments
Sep. 30, 2013
Equity Method Investments
Sep. 30, 2014
Equity Method Investments
Sep. 30, 2013
Equity Method Investments
Sep. 30, 2014
Class A Common Stock
Jun. 26, 2013
Class A Common Stock
Sep. 30, 2014
Class B Common Stock
Sep. 30, 2014
Class B Common Stock
Slp
Summary Of Significant Accounting Policies [Line Items]                                    
Ownership percentage in a subsidiary                             63.00% 63.00%    
Number of operating segment     1                              
Cash equivalents, maximum maturity period     90 days                              
Equity method investments, unrealized intercompany profit (loss) not eliminated amount     $ 0                              
Impairment charges related to equity method investments                     0 0 0 0        
Property, plant and equipment, useful life               10 years 3 years 7 years                
Number of reporting unit     1   1                          
Impairment charges on goodwill $ 0 $ 0 $ 0 $ 0                            
Identifiable finite-lived intangible assets, useful life           3 years 20 years                      
Common stock, voting rights                             1 vote per share   1 vote per share  
Class of share exchangeable to another class                                 one share of Class A common stock one share of Class A common stock