Benefit Plans - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) installment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2016 USD ($) age	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2008 USD ($) age	Dec. 31, 2003 USD ($) age
Defined Benefit Plan Disclosure [Line Items]
Percent of match	50.00%
Employer matching contribution, percent of employees' gross pay	6.00%
Company's contributions to employees salary	$ 2,200,000	$ 2,200,000	$ 1,600,000
Minimum period of service for retirement	5 years
Maximum payment period for benefits	10 years
Director
Defined Benefit Plan Disclosure [Line Items]
Accrued plan cost included in other liabilities	$ 618,000	627,000
Net actuarial loss	0	0
Minimum
Defined Benefit Plan Disclosure [Line Items]
Payment for pension and other postretirement benefits	5,000
Maximum
Defined Benefit Plan Disclosure [Line Items]
Payment for pension and other postretirement benefits	17,500
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Retirement age of CEO | age				66
Compensation expense	104,000	(262,000)	163,000
Accrued liabilities	3,000,000	3,200,000
Supplemental Employee Retirement Plan | Former Chief Executive Officer
Defined Benefit Plan Disclosure [Line Items]
Annual retirement benefit								$ 150,000
Retirement benefit period								15 years
Retirement age of CEO | age								65
Supplemental Employee Retirement Plan | CEO
Defined Benefit Plan Disclosure [Line Items]
Annual retirement benefit							$ 150,000
Retirement benefit period							15 years
Retirement age of CEO | age							65
Supplemental Employee Retirement Plan | Former Regional President
Defined Benefit Plan Disclosure [Line Items]
Annual retirement benefit				$ 84,500			$ 90,000
Retirement benefit period				15 years			10 years
Retirement age of CEO | age							65
Supplemental Employee Retirement Plan | Somerset Hills Bancorp
Defined Benefit Plan Disclosure [Line Items]
Retirement benefit period						15 years
Supplemental Employee Retirement Plan | Somerset Hills Bancorp | CEO
Defined Benefit Plan Disclosure [Line Items]
Annual retirement benefit						$ 48,000
Supplemental Employee Retirement Plan | Somerset Hills Bancorp | CFO
Defined Benefit Plan Disclosure [Line Items]
Annual retirement benefit						$ 24,000
Deferred Compensation Agreement
Defined Benefit Plan Disclosure [Line Items]
Expense related to the deferred compensation plan	241,000	450,000	331,000
Accrued liability on deferred compensation plans	$ 2,600,000	2,400,000
Deferred Compensation Agreement | CEO
Defined Benefit Plan Disclosure [Line Items]
Employer monthly contribution					$ 16,500
Number of consecutive installments payments | installment	180
Deferred Compensation Agreement | Minimum | CEO
Defined Benefit Plan Disclosure [Line Items]
Range of return on equity					0.00%
Deferred Compensation Agreement | Maximum | CEO
Defined Benefit Plan Disclosure [Line Items]
Range of return on equity					15.00%
Elective Deferral Plan
Defined Benefit Plan Disclosure [Line Items]
Expense related to the deferred compensation plan	$ 372,000	346,000	$ 183,000
Accrued liability on deferred compensation plans	5,400,000	$ 4,500,000
Elective Deferral Plan | Eligible Executives
Defined Benefit Plan Disclosure [Line Items]
Deferral account, interest rate					75.00%
Elective Deferral Plan | Minimum | Eligible Executives
Defined Benefit Plan Disclosure [Line Items]
Range of return on equity					0.00%
Elective Deferral Plan | Maximum | Eligible Executives
Defined Benefit Plan Disclosure [Line Items]
Range of return on equity					15.00%
Director's Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Plan assets of director's retirement plan	$ 0
Discount rate of directors retirement plan	4.70%	4.91%	2.49%
Contribution to the director's retirement plan	$ 29,000