Fair Value Measurements - Carrying Amount and Fair Values of the Company's Assets and Liabilities Measured on a Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Non-financial liabilities (Level 3 measurement):
Acquisition-related contingent consideration	$ 4.8	$ 4.6
Recurring [Member] | Carrying Amount [Member]
Non-derivatives:
Cash and cash equivalents	91.4	80.2
Short-term investments	6.0	6.6
Non-derivatives:
Long-term debt (including current portion)	139.5	148.0
Recurring [Member] | Carrying Amount [Member] | Derivatives (Level 1 Measurement) [Member]
Derivatives (Level 1 measurement):
Foreign currency forward exchange contracts	0.4	1.0
Recurring [Member] | Carrying Amount [Member] | Non-financial Assets and Liabilities (Level 3 Measurement) [Member]
Non-financial liabilities (Level 3 measurement):
Acquisition-related contingent consideration	4.8	4.6
Recurring [Member] | Carrying Amount [Member] | Non-financial Assets and Liabilities (Level 3 Measurement) [Member] | Stock Equivalent Units [Member]
Non-financial liabilities (Level 3 measurement):
Stock equivalent units	7.6	12.1
Recurring [Member] | Fair Value [Member]
Non-derivatives:
Cash and cash equivalents	91.4	80.2
Short-term investments	6.0	6.6
Non-derivatives:
Long-term debt (including current portion)	139.5	148.0
Recurring [Member] | Fair Value [Member] | Derivatives (Level 1 Measurement) [Member]
Derivatives (Level 1 measurement):
Foreign currency forward exchange contracts	0.4	1.0
Recurring [Member] | Fair Value [Member] | Non-financial Assets and Liabilities (Level 3 Measurement) [Member]
Non-financial liabilities (Level 3 measurement):
Acquisition-related contingent consideration	4.8	4.6
Recurring [Member] | Fair Value [Member] | Non-financial Assets and Liabilities (Level 3 Measurement) [Member] | Stock Equivalent Units [Member]
Non-financial liabilities (Level 3 measurement):
Stock equivalent units	$ 7.6	$ 12.1