Fair Value Measurements, Balance Sheet Grouping (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Financial Assets [Abstract]
Securities available-for-sale	$ 164,112,000	$ 178,476,000
Loans held for sale	383,389,000	220,123,000
Mortgage servicing rights	6.4		$ 186,000
Financial Liabilities [Abstract]
Advance payments by borrowers for taxes	20,828,000	4,212,000
Carrying Amount [Member]
Financial Assets [Abstract]
Cash and cash equivalents	76,919,000	74,300,000
Securities available-for-sale	164,112,000	178,476,000
Loans held for sale	383,389,000	220,123,000
Loans receivable	1,433,803,000	1,388,031,000
FHLB stock	26,720,000	21,150,000
Accrued interest receivable	5,061,000	5,344,000
Mortgage servicing rights	4,966,000	282,000
Mortgage banking derivative assets	10,741,000	1,835,000
Interest rate swap assets	6,289,000	680,000
Financial Liabilities [Abstract]
Deposits	1,157,666,000	1,067,776,000
Advance payments by borrowers for taxes	20,828,000	4,212,000
Borrowings	599,102,000	483,562,000
Accrued interest payable	1,404,000	1,559,000
Mortgage banking derivative liabilities	2,112,000	0
Interest rate swap liabilities	6,289,000	680,000
Fair Value [Member]
Financial Assets [Abstract]
Cash and cash equivalents	76,919,000	74,300,000
Securities available-for-sale	164,112,000	178,476,000
Loans held for sale	383,389,000	220,123,000
Loans receivable	1,509,054,000	1,426,224,000
FHLB stock	26,720,000	21,150,000
Accrued interest receivable	5,061,000	5,344,000
Mortgage servicing rights	6,388,000	282,000
Mortgage banking derivative assets	10,741,000	1,835,000
Interest rate swap assets	6,289,000	680,000
Financial Liabilities [Abstract]
Deposits	1,157,834,000	1,070,083,000
Advance payments by borrowers for taxes	20,828,000	4,212,000
Borrowings	619,497,000	483,846,000
Accrued interest payable	1,404,000	1,559,000
Mortgage banking derivative liabilities	2,112,000	0
Interest rate swap liabilities	6,289,000	680,000
Fair Value [Member] | Level 1 [Member]
Financial Assets [Abstract]
Cash and cash equivalents	76,919,000	65,800,000
Securities available-for-sale	0	0
Loans held for sale	0	0
Loans receivable	0	0
FHLB stock	0	0
Accrued interest receivable	5,061,000	5,344,000
Mortgage servicing rights	0	0
Mortgage banking derivative assets	0	0
Interest rate swap assets	0	0
Financial Liabilities [Abstract]
Deposits	418,249,000	328,005,000
Advance payments by borrowers for taxes	20,828,000	4,212,000
Borrowings	0	0
Accrued interest payable	1,404,000	1,559,000
Mortgage banking derivative liabilities	0	0
Interest rate swap liabilities	0	0
Fair Value [Member] | Level 2 [Member]
Financial Assets [Abstract]
Cash and cash equivalents	0	8,500,000
Securities available-for-sale	164,112,000	178,476,000
Loans held for sale	383,389,000	220,123,000
Loans receivable	0	0
FHLB stock	26,720,000	21,150,000
Accrued interest receivable	0	0
Mortgage servicing rights	0	0
Mortgage banking derivative assets	0	0
Interest rate swap assets	6,289,000	680,000
Financial Liabilities [Abstract]
Deposits	739,585,000	742,078,000
Advance payments by borrowers for taxes	0	0
Borrowings	619,497,000	483,846,000
Accrued interest payable	0	0
Mortgage banking derivative liabilities	0	0
Interest rate swap liabilities	6,289,000	680,000
Fair Value [Member] | Level 3 [Member]
Financial Assets [Abstract]
Cash and cash equivalents	0	0
Securities available-for-sale	0	0
Loans held for sale	0	0
Loans receivable	1,509,054,000	1,426,224,000
FHLB stock	0	0
Accrued interest receivable	0	0
Mortgage servicing rights	6,388,000	282,000
Mortgage banking derivative assets	10,741,000	1,835,000
Interest rate swap assets	0	0
Financial Liabilities [Abstract]
Deposits	0	0
Advance payments by borrowers for taxes	0	0
Borrowings	0	0
Accrued interest payable	0	0
Mortgage banking derivative liabilities	2,112,000	0
Interest rate swap liabilities	$ 0	$ 0