Loans Receivable and Allowance for Loan Losses (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Participation interest in loans originated	$ 196,300,000	$ 242,600,000
Loans receivable, gross	2,343,937,000	2,330,018,000
Non-accrual loans, interest income lost	1,300,000	1,500,000
Loans returned to accrual, interest income	1,200,000	710,000
Loans Receivable >90 Days and Accruing	3,124,000	333,000
Loans acquired with deteriorated credit quality, fair value	668,000,000,000	1,100,000
Troubled debt restructurings, subsequent default, amount	0	$ 216,000
Troubled debt restructuring, subsequent default, number | loan		1
Transfers from non-accretable differences	0	$ 0
IA Bancorp [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of loans acquired	1,000,000.0	1,400,000
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	39,200,000	68,600,000
Substandard [Member] | Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	$ 39,200,000	$ 68,600,000