Derivatives and Hedging Activities - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) item	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Oct. 31, 2018 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Participating Mortgage Loans, Mortgage Obligations, Amount	$ 27,600
Number of Participation loans purchased | item	4
Interest Rate Swap | Cash flow hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount				$ 400,000
Derivative, Fixed Interest Rate				3.018%
Expected interest income on termination		$ 2,000
Not Designated as Hedging Instrument | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	$ 139,300		$ 142,800
Number of Interest Rate Derivatives Held	18		19
Valley Bank | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Loans Acquired | item	7
Valley Bank | Not Designated as Hedging Instrument | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of Loans Acquired | item	7
Number of Loans Paid Off | item	5
Derivative, Notional Amount	$ 559
Number of Interest Rate Derivatives Held	2