Employee Benefit Plans (Narrative) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Defined contribution plan, cost	$ 23,800,000	$ 17,900,000
Percentage of equity investments in mutual fund	68.00%
Net periodic benefit cost, Expected return on plan assets	7.25%	7.25%	7.25%
Expected defined benefit plans contribution within a year	$ 1,200,000
Number of stock plans	3
Dividends, share-based compensation	$ 0.75	$ 0.72	$ 0.71
Weighted-average risk-free interest rate	0.77%	0.19%	1.65%
Options awarded during period	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	777,687
Base-year adjusted net revenue amount	$ 426,600,000
Base-year calculation basis point adjustment	0.30%
Percentage level of achievement - 13 percent average growth	13.00%
Award payout percentage of target at 50 percent	50.00%
Percentage level of achievement - 19 percent average growth	19.00%
Award payout percentage of target at 100 percent	100.00%
Percentage level of achievement - 25 percent average growth	25.00%
Award payout percentage of target at 150 percent	150.00%
Award payout percentage at less than 25th percentile level of achievement	0.00%
Award payout percentage at the 25th percentile level of achievement	50.00%
Award payout percentage at the 50th percentile level of achievement	100.00%
Award payout percentage at the 75th percentile level of achievement	150.00%
Performance Shares [Member] | Pro Forma [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Granted in period, number of shares/units	30,723	48,409	34,317
Equity Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Target asset allocation percentage	62.00%
Fixed Income Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Target asset allocation percentage	36.00%
Two Thousand Fifteen Plan [Member] | Stock Options [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years	4 years
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]
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
Minimum [Member] | Performance Shares [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Percentage level of achievement - less than 13 percent average growth	13.00%
Award payout percentage of target at 0 percent	0.00%
Maximum [Member] | Performance Shares [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Granted in period, number of shares/units	46,086	72,618	51,479
Deferred Profit Sharing [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Defined contribution plan, cost	$ 0	$ 0	$ 0
Other Pension Plan [Member] | Qualified Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Defined contribution plan, cost			$ 28,900,000
Participants contribution eligible for match	100.00%
Other Pension Plan [Member] | Qualified Plan [Member] | Minimum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Maximum annual contributions per employee, percent	2.00%
Other Pension Plan [Member] | Qualified Plan [Member] | 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%