Employee Benefit Plans - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items]
Grant awards	4,000,000
Incentive compensation program expiration	2031-02
Fair value of grants recognition period		5 years
Vested of common stock		1
Issuance of common stock		1
Dividend equivalents charged against retained earnings when common stock dividends were declared		$ 1,855,000	$ 1,485,000	$ 1,279,000
Compensation expense		$ 4,775,000	3,997,000	3,130,000
Employer matching contribution percent		50.00%
Employee compensation		3.00%
Contributions, net of forfeitures		$ 382,000	$ 379,000	$ 353,000
Restricted Stock Units [Member]
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items]
Restricted stock awarded		238,850	196,050	191,050
Termination of grant		10 years
RSUs vest starting period from date of grant		1 year
Annual rate of vest of total number of RSUs		20.00%
Number of outstanding RSUs		1,117,250	921,400	837,475	702,025
Number of vested RSUs		554,556	456,190	420,635	349,135
Restricted Stock Units [Member] | 2004 Omnibus Incentive Compensation Plan [Member]
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items]
Fair value of grants recognition period		5 years
Compensation expense		$ 4,745,000	$ 3,976,000	$ 3,109,000
Weighted average period		4 years
Number of outstanding RSUs		1,117,250
Number of vested RSUs		554,556
Intrinsic value of outstanding RSUs		$ 37,819,000
Intrinsic value of vested RSUs		18,772,000
Restricted Stock Units [Member] | 2004 Incentive Plan [Member]
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items]
Unrecognized compensation cost		$ 12,278,000
Supplemental Employee Retirement Plan [Member]
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items]
Executive compensation		10.00%
Distribution from supplemental plan		$ 95,000,000
Tranche One [Member]
Schedule Of Share Based Compensation Arrangements By Share Based Payment Award Options [Line Items]
Incentive compensation program vesting percentage		20.00%