Stock-Based Compensation (Allocation of Stock-Based Compensation Costs by Plan) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Allocated Share-based Compensation Expense | $ 3.8 | $ 4.6 | $ 7.8 | $ 8.9 |
Cost of Revenue [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Allocated Share-based Compensation Expense | 2.0 | 2.1 | 4.0 | 4.1 |
Selling and Marketing Expense [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Allocated Share-based Compensation Expense | 0.5 | 0.6 | 1.0 | 1.1 |
General and Administrative Expense [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
Allocated Share-based Compensation Expense | $ 1.3 | $ 1.9 | $ 2.8 | $ 3.7 |