Postretirement Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Capped eligible compensation	$ 1.0
Maximum allowed investment percentage in any single issuer in pension plan assets at time of purchase	10.00%
SERP
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions	$ 17.9	$ 21.9	$ 21.6