Share-based Compensation - Summary of Stock Option Activity (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Options - Outstanding at beginning of period (in shares)	4,301
Options - Granted (in shares)	686
Options - Exercised (in shares)	(261)	(700)	(600)
Options - Cancelled (in shares)	(301)
Options - Forfeited (in shares)	(43)
Options - Outstanding at end of period (in shares)	4,382	4,301
Weighted average exercise price per share - Outstanding at beginning of period (in dollars per share)	$ 63.24
Weighted average exercise price per share - Granted (in dollars per share)	49.72
Weighted average exercise price per share - Exercised (in dollars per share)	59.88
Weighted average exercise price per share - Cancelled (in dollars per share)	61.13
Weighted average exercise price per share - Forfeited (in dollars per share)	52.70
Weighted average exercise price per share - Outstanding at end of period (in dollars per share)	$ 61.57	$ 63.24
Weighted average remaining contractual term - Outstanding	5 years 1 month 6 days	4 years 9 months 18 days