Revenue Recognition (Disaggregated) (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Disaggregation of Revenue [Line Items] | |||
| Revenue | $ 272,458 | $ 244,175 | $ 208,130 |
| United States | |||
| Disaggregation of Revenue [Line Items] | |||
| Revenue | 187,852 | 169,547 | 147,713 |
| Canada | |||
| Disaggregation of Revenue [Line Items] | |||
| Revenue | 22,700 | 20,765 | 16,694 |
| All other international sources | |||
| Disaggregation of Revenue [Line Items] | |||
| Revenue | $ 61,906 | $ 53,863 | $ 43,723 |
| International revenue (excluding Canada) as a percent of total revenue | 23.00% | 22.00% | 21.00% |