Common Stock Repurchase Programs - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Aug. 31, 2018
Common Stock [Line Items]
Common stock authorized for repurchase			$ 500.0
Company's Common stock repurchased		$ 107.2
Restricted Stock [Member]
Common Stock [Line Items]
Number of shares withheld to satisfy minimum statutory tax withholding obligations	0.5
Amount withheld to satisfy minimum statutory tax withholding obligations	$ 8.5