Common Stock Repurchase Programs - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Dec. 31, 2020	Aug. 31, 2018
Common Stock [Line Items]
Stock repurchased during period, shares					0
Common stock authorized for repurchase							$ 500.0
Company's Common stock remained available for repurchase						$ 98.7
Common Stock [Member]
Common Stock [Line Items]
Stock repurchased during period, shares	8,000	82,000	34,000	125,000
Restricted Stock [Member]
Common Stock [Line Items]
Number of shares withheld to satisfy minimum statutory tax withholding obligations					100,000
Amount withheld to satisfy minimum statutory tax withholding obligations					$ 2.2