Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Share Repurchase Program (Details)

v3.6.0.2
Summary of Significant Accounting Policies - Share Repurchase Program (Details) - USD ($)
12 Months Ended
Dec. 31, 2016
Apr. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Treasury stock, shares, acquired 1,298,418  
Treasury stock, value, acquired $ 6,387,000  
Repurchase fees $ 52,000  
Class A Common Stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock repurchase program, authorized amount (up to)   $ 10,000,000
Treasury Stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Treasury stock, shares, acquired (1,298,418)  
Treasury stock, value, acquired $ 6,387,000