Property, Plant, and Equipment - Schedule of Property, Plant, and Equipment (Detail) - USD ($) $ in Millions |
Sep. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Property Plant And Equipment [Line Items] | ||
| Total property, plant, and equipment | $ 384.6 | $ 361.5 |
| Accumulated depreciation | (284.0) | (259.5) |
| Property, plant, and equipment, net | 100.6 | 102.0 |
| Land [Member] | ||
| Property Plant And Equipment [Line Items] | ||
| Total property, plant, and equipment | 7.5 | 7.5 |
| Software [Member] | ||
| Property Plant And Equipment [Line Items] | ||
| Total property, plant, and equipment | 218.5 | 197.4 |
| Machinery and Equipment [Member] | ||
| Property Plant And Equipment [Line Items] | ||
| Total property, plant, and equipment | 118.8 | 120.3 |
| Buildings and Improvements [Member] | ||
| Property Plant And Equipment [Line Items] | ||
| Total property, plant, and equipment | $ 39.8 | $ 36.3 |