Cost Reduction Actions - Additional Information (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($) Employee	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) Employee	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 26.9	$ 0.0	$ 118.5
Severance costs	22.1		78.8
Asset impairments and other expenses related to the cost reduction effort			39.7
Asset impairment Charges			20.2
Other expenses related to the cost reduction effort	4.8		19.5
United States
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 4.2		$ 27.9
Number of employees | Employee	175		700
Non-US
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 17.9		$ 50.9
Number of employees | Employee	337		782
Scenario, Forecast
Restructuring Cost and Reserve [Line Items]
Estimated pretax restructuring charges				$ 300.0
Cost of Revenue | Services
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 11.5		$ 52.3
Cost of Revenue | Technology
Restructuring Cost and Reserve [Line Items]
Restructuring charges			0.3
Selling, general and administrative expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges	13.3		53.5
Research and development expenses
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2.1		$ 12.4