Earnings Per Share - Additional Information (Detail) - 2011 Share Repurchase Program [Member] - shares	3 Months Ended	6 Months Ended	118 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2021	Mar. 16, 2016	Aug. 18, 2011
Equity, Class of Treasury Stock [Line Items]
Maximum amount of shares authorized for repurchase				10,000,000.0	5,000,000.0
Total Number of Shares Repurchased	500,000	1,360,000	8,300,000
Increase in shares authorized for repurchase				5,000,000.0