Recently Issued Accounting Standards - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax benefit on exercise of stock options			$ 15.9
Excess tax benefit from exercise of stock based compensation, financing activities			16.4
Employee withholding taxes reclassified into financing activities		$ 9.0	13.6
ASU No. 2016-09 | Adjustments for New Accounting Principle, Early Adoption | Restatement Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax benefit on exercise of stock options	$ (9.0)	(14.2)
Excess tax benefit reclassified to income tax expense	$ 9.0	14.2
Excess tax benefit from exercise of stock based compensation, financing activities		(14.2)
Excess tax benefit from exercise of stock based compensation, operating activities		14.2
Employee withholding taxes reclassified from operating activities		(9.0)	(13.6)
Employee withholding taxes reclassified into financing activities		$ 9.0	$ 13.6
Increase in basic and diluted earning per share common share	$ 0.06	$ 0.09