Supplemental Disclosures of Cash Flow Information - Additional Information (Detail) - Qualified Contributory Savings and Thrift 401(k) Plan [Member] - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Matching contributions by employer, percentage	100.00%
Percentage of eligible compensation for matching contributions by employer	5.00%
Matching contributions vesting schedule	5 years
Contribution expense to plan	$ 40.0	$ 34.5
Employer match on eligible compensation	5.00%
Decreased net cash provided by operating activities		0.6
Decreased net cash used by investing activities		$ 0.6