Stock-Based Compensation Plans - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Options Outstanding, Beginning balance | shares	3,432,870
Stock Options Outstanding, Granted | shares	200
Stock Options Outstanding, Assumed in acquisition | shares	1,843,159
Stock Options Outstanding, Exercised | shares	(954,684)
Stock Options Outstanding, Expired | shares	(97,835)
Stock Options Outstanding, Ending balance | shares	4,223,710
Stock Options Outstanding, Exercisable | shares	4,223,266
Weighted-Average Exercise Price, Outstanding, Beginning balance | $ / shares	$ 105.31
Weighted-Average Exercise Price, Granted | $ / shares	113.16
Weighted-Average Exercise Price, Assumed in acquisition | $ / shares	156.82
Weighted-Average Exercise Price, Exercised | $ / shares	107.06
Weighted-Average Exercise Price, Expired | $ / shares	137.50
Weighted-Average Exercise Price, Outstanding, Ending balance | $ / shares	126.65
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 126.65
Weighted-Average Life (In Years), Outstanding, Ending balance	1 year 8 months 12 days
Weighted-Average Life (In Years), Exercisable	1 year 8 months 12 days
Aggregate Intrinsic Value, Outstanding, Ending balance | $	$ 43,761
Aggregate Intrinsic Value, Exercisable | $	$ 43,755