Deposits - Deposit Liabilities (Details)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Nov. 15, 2018 USD ($)	Jan. 22, 2016 Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Noninterest-bearing checking	$ 260,131,000	$ 221,107,000
Interest-bearing checking	177,972,000	151,103,000
Savings	118,845,000	122,344,000
Money market	270,489,000	282,595,000
Certificates of deposit less than $100,000	277,988,000	243,193,000
Certificates of deposit of $100,000 through $250,000	181,402,000	154,095,000
Certificates of deposit of $250,000 and over	92,110,000	86,357,000
Escrow accounts related to mortgages serviced	13,471,000	13,425,000
Total deposits	1,392,408,000	1,274,219,000
Federal Reserve Bank required deposit reserves	0	17,400,000
Money Market Funds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-bearing Domestic Deposit, Brokered	6,200,000	1,000
Certificates of Deposit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-bearing Domestic Deposit, Brokered	141,400,000	116,700,000
Bank of America
Accounts, Notes, Loans and Financing Receivable [Line Items]
Remaining Branch Purchase Deposits	117,100,000	120,000,000
Number of Bank Branches | Office				4
Anchor Bancorp
Accounts, Notes, Loans and Financing Receivable [Line Items]
Remaining Branch Purchase Deposits	$ 299,000,000	$ 321,100,000	$ 356,811,000