Goodwill and Other Intangible Assets - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) reportingUnit	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Jan. 06, 2022 USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 271,829,000		$ 271,829,000		$ 271,829,000
Number of reporting units | reportingUnit			1
Goodwill, impairment loss	0	$ 0	$ 0	$ 0
Amortization of intangible assets	501,000	581,000	1,529,000	1,770,000
1st Constitution Bancorp
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill						$ 115,600,000
Core Deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets	7,600,000		7,600,000		$ 9,100,000
Amortization of intangible assets	$ 501,000	$ 581,000	$ 1,500,000	$ 1,800,000
Core Deposits | 1st Constitution Bancorp
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets						$ 9,000,000