Weighted Average Shares - Calculation of Weighted Average Shares (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Basic weighted-average common shares outstanding	171,194	172,333	173,287
Effect of dilutive stock options	4,075	5,073	6,264
Diluted weighted-average common and common-equivalent shares outstanding	175,269	177,406	179,551