Summary of Stock Option Activity (Detail) - Stock Option Awards - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Options outstanding, shares
Beginning Balance	1,480	992	886
Granted	470	710	175
Exercised	(51)	(21)	(12)
Forfeited/Expired	(265)	(201)	(57)
Ending Balance	1,634	1,480	992
Exercisable as of December 31, 2019	847
Expected to vest as of December 31, 2019	787
Total	1,634
Weighted Average Exercise Price Per Share
Beginning Balance	$ 137.16	$ 145.28	$ 143.89
Granted	150.88	130.27	169.04
Exercised	128.17	121.13	143.35
Forfeited/Expired	135.88	154.49	196.52
Ending Balance	141.60	$ 137.16	$ 145.28
Exercisable as of December 31, 2019	137.97
Expected to vest as of December 31, 2019	145.50
Total	$ 141.60
Aggregate Intrinsic Value
Exercised	$ 799	$ 196	$ 541
Exercisable as of December 31, 2019	12,251
Expected to vest as of December 31, 2019	3,826
Total	$ 16,077
Weighted Average Remaining Contractual Term (Years)
Exercisable as of December 31, 2019	5 years
Expected to vest as of December 31, 2019	9 years
Total	6 years 10 months 24 days