Related Party Transactions - Transactions with USAA (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Related Party Transaction [Line Items] | |||
| Amounts due from related party | $ 328 | $ 1,865 | |
| Amounts due to related party | 7,490 | 4,954 | |
| USAA | |||
| Related Party Transaction [Line Items] | |||
| Amounts due from related party | 300 | 1,900 | |
| Amounts due to related party | 7,800 | 4,700 | |
| USAA | Selling and Marketing Expense | |||
| Related Party Transaction [Line Items] | |||
| Sales and marketing expense | $ 14,000 | $ 15,200 | $ 8,800 |