Employee Benefit Plans (Narrative) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Percentage of equity investments in mutual fund	85.00%
Net periodic benefit cost, Expected return on plan assets	7.00%	7.25%	7.25%
Expected defined benefit plans contribution within a year	$ 1,100,000
Participants contribution eligible for match	100.00%
Defined contribution plan, cost	$ 32,300,000	$ 28,000,000	$ 23,800,000
Number of stock plans	3
Dividends, share-based compensation	$ 0.92	$ 0.87	$ 0.75
Weighted-average risk-free interest rate	5.01%	4.45%	0.77%
Options awarded during period	0	0	0
Performance Shares [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	205,090
Performance Shares [Member] | Pro Forma [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Granted in period, number of shares/units	66,471	35,015	30,723
Equity Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Target asset allocation percentage	31.00%
Fixed Income Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Target asset allocation percentage	63.00%
Two Thousand Fifteen Plan [Member] | Stock Options [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Vesting period of options awarded, years	4 years
Two Thousand Fifteen Plan [Member] | Non Vested Stock Awards and Stock Units [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Two Thousand Fifteen Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | 2021
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years	3 years
Two Thousand Fifteen Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | Prior to 2021
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years	4 years
Two Thousand Fifteen Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | 2023
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years	3 years
Two Thousand Fifteen Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | 2022
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years	3 years
Minimum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Maximum annual contributions per employee, percent	2.00%
Maximum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Maximum annual contributions per employee, percent	50.00%
Employer matching contribution, percent of employees' gross pay	6.00%
Maximum [Member] | Performance Shares [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Granted in period, number of shares/units	99,710	52,527	46,086