Loans - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) contract loan	Dec. 31, 2020 USD ($) contract loan	Dec. 31, 2019 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable on loans	$ 13,900,000	$ 16,100,000
Net deferred loan fees	(5,800,000)	(10,000,000)
Overdraft balances included in home equity and consumer loans	184,000	650,000
Residential loans pledged for potential borrowings at the Federal Home Loan Bank of New York	$ 2,300,000,000	$ 2,280,000,000
Number of loans still accruing | loan	1	1
Financing receivable, 90 days or more past due, still accruing	$ 1,000	$ 1,000
Financing receivable, troubled debt restructuring	3,500,000	5,000,000
Financing receivable, accrual, troubled debt restructuring	3,300,000	3,900,000
Financing receivable nonaccrual troubled debt restructuring	$ 127,000	$ 1,100,000
Number of contracts | contract		0
Financing receivable, troubled debt restructuring, subsequent default, number of contracts | contract	0
Loans to related parties	$ 64,000,000	$ 75,700,000
Loans to related parties, additions	5,000,000
Repayment of loan from related parties	16,700,000
Loans held for sale	1,943,000	1,335,000
Residential real estate acquired through disclosure	0	0
Other repossessed assets owned	0	0
Writedown of other repossessed assets	0	39,000	$ 153,000
COVID-19
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, deferred	0
Paycheck Protection Program ("PPP")
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss and fee	56,600,000	284,600,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, 90 days or more past due, still accruing	1,000	1,000
Financing receivable, troubled debt restructuring	$ 115,000
Number of contracts | contract	1
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, 90 days or more past due, still accruing		$ 0
Financing receivable, troubled debt restructuring, subsequent default, number of contracts | contract		2
Recorded Investment		$ 83,000
Residential And Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, nonaccrual, in the process of foreclosure	$ 930,000	$ 1,700,000