Segment Information (Details) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
|
| Segment Reporting Information [Line Items] | ||||
| Total consolidated revenue | 100.00% | 100.00% | 100.00% | 100.00% |
| Canada [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Total consolidated revenue | 3.50% | 3.90% | 3.00% | 4.20% |
| Other foreign markets [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Total consolidated revenue | 18.60% | 14.50% | 18.80% | 12.80% |
| U.K. [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Total consolidated revenue | 21.60% | 20.00% | 22.60% | 20.40% |
| U.S. [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Total consolidated revenue | 56.30% | 61.60% | 55.60% | 62.60% |