Summary of Significant Accounting Policies - Share Repurchase Agreement (Details) - USD ($) |
3 Months Ended | 6 Months Ended | |
|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2016 |
Apr. 30, 2016 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Open market purchase of treasury shares | $ 1,949,000 | ||
| Common Class A | |||
| 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] | |||
| Open market purchase of common shares (in shares) | 417,698 | 417,698 | |
| Open market purchase of treasury shares | $ 1,949,000 | $ 1,949,000 |