Business Combinations - Narrative (Details)		3 Months Ended		5 Months Ended	6 Months Ended
	Jan. 06, 2022 USD ($) branch $ / shares shares	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2023 USD ($) shares	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Business Acquisition [Line Items]
Assets		$ 10,897,966,000			$ 10,897,966,000		$ 10,783,840,000
Loans		8,027,322,000			8,027,322,000		7,795,786,000
Deposits		8,444,681,000			8,444,681,000		$ 8,567,471,000
Merger-related expenses		$ 242,000	$ 0		537,000	$ 4,585,000
Net PCD loans	$ 124,431,000
Provident Financial Services, Inc. (Combined) | Forecast
Business Acquisition [Line Items]
Assets				$ 25,000,000,000
Loans				18,000,000,000
Deposits				$ 20,000,000,000
Provident Financial Services, Inc. (Combined) | Provident Financial Services, Inc. | Forecast
Business Acquisition [Line Items]
Business combination, merger, shareholder interest in combined entity, ownership percentage				58.00%
Provident Financial Services, Inc. (Combined) | Lakeland Shareholders | Forecast
Business Acquisition [Line Items]
Business combination, merger, shareholder interest in combined entity, ownership percentage				42.00%
Lakeland Bancorp, Inc | Forecast
Business Acquisition [Line Items]
Business combination, consideration transferred				$ 1,300,000,000
Lakeland Bancorp, Inc | Provident Financial Services, Inc. | Forecast
Business Acquisition [Line Items]
Business combination, consideration transferred, equity interests issued and issuable, entity shares issued per acquiree share (in shares) | shares				0.8319
1st Constitution Bancorp
Business Acquisition [Line Items]
Business combination, consideration transferred, equity interests issued and issuable, entity shares issued per acquiree share (in shares) | shares	1.3577
Number of operating bank branches | branch	25
Consideration paid through common stock (in shares) | shares	14,020,495
Business acquisition, share price (in usd per share) | $ / shares	$ 25.55
Business acquisition, average strike price (in usd per share) | $ / shares	$ 15.95
Business combination, consideration transferred, cash payments for equity interest	$ 559,000
Net PCD loans					$ 74,200,000