Allowance for Credit Losses - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing receivable, collectively evaluated for impairment	$ 7,005,822,000		$ 5,954,950,000
Financing receivable, allowance for credit losses, collectively evaluated for impairment	59,086,000		53,796,000
Financing receivable, individually evaluated for impairment and acquired with deteriorated credit quality	132,000,000
Financing receivable, allowance for credit losses, individually evaluated for impairment and acquired with deteriorated credit quality	8,000,000
Loans, Individually evaluated for impairment	17,659,000		20,261,000
Allowance for credit losses, Individually evaluated for impairment	8,026,000		4,251,000
Charge-offs	7,804,000	$ 1,270,000
Debt securities, available-for-sale, allowance for credit loss	1,300,000		83,000
Debt securities, held-to-maturity, allowance for credit loss	199,000		181,000
Debt securities, available-for-sale, credit loss expense (reversal)	1,200,000	142,000
Debt securities, held-to-maturity, credit loss expense (reversal)	18,000	0
Debt securities, accrued interest after allowance for credit loss	7,900,000		5,300,000
Off-balance sheet, credit loss, liability	2,800,000		$ 2,300,000
Off-balance sheet, credit loss, liability, credit loss expense (reversal)	440,000	24,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans, Individually evaluated for impairment	114,300,000
Allowance for credit losses, Individually evaluated for impairment	4,600,000
Charge-offs	170,000	$ 1,270,000
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | 1st Constitution Bancorp
Financing Receivable, Allowance for Credit Loss [Line Items]
Charge-offs	7,600,000
Nonperforming Financial Instruments
Financing Receivable, Allowance for Credit Loss [Line Items]
Charge-offs	1,100,000
Loans sold	$ 10,100,000