Revenue Recognition - Contract Costs (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |
|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2018 |
Sep. 30, 2017 |
|
| Capitalized Contract Cost [Line Items] | |||
| Contract cost amortization | $ 1,900 | $ 0 | |
| Capitalized contract cost, amortization period | 5 years | 5 years | |
| Bonuses and Commissions | |||
| Capitalized Contract Cost [Line Items] | |||
| Contract cost assets | $ 2,000 | $ 2,000 | |
| Contract cost amortization | 100 | 200 | |
| Contract Fulfillment Costs | |||
| Capitalized Contract Cost [Line Items] | |||
| Contract cost assets | 12,300 | 12,300 | |
| Contract cost amortization | $ 600 | $ 1,700 | |