Loans - Average Recorded Investment and Interest Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Average Recorded Investment
Total	$ 20,202	$ 21,900	$ 20,451	$ 22,042
Interest Income
Total	277	206	436	416
Real Estate \| Commercial
Average Recorded Investment
Total	16,857	17,951	17,012	17,998
Interest Income
Total	232	153	343	304
Real Estate \| One-to-Four Family
Average Recorded Investment
Total	2,383	2,645	2,415	2,659
Interest Income
Total	27	32	61	66
Real Estate \| Multifamily
Average Recorded Investment
Total	854	1,179	915	1,258
Interest Income
Total	18	21	31	44
Real Estate \| Home equity and lines of credit
Average Recorded Investment
Total	53	59	53	59
Interest Income
Total	0	0	1	2
Real Estate \| Home equity and lines of credit \| Pass
Average Recorded Investment
With No Allowance Recorded	20	26	20	26
Interest Income
With No Allowance Recorded	0	0	0	1
Real Estate \| Home equity and lines of credit \| Substandard
Average Recorded Investment
With a Related Allowance Recorded	33	33	33	33
Interest Income
With a Related Allowance Recorded	0		1	1
Commercial and Industrial
Average Recorded Investment
Total	55	66	56	68
Interest Income
Total	0	0	0	0
Commercial and Industrial \| Special Mention
Average Recorded Investment
With a Related Allowance Recorded	18	20	18	20
Interest Income
With a Related Allowance Recorded	0		0	0
Commercial and Industrial \| Substandard
Average Recorded Investment
With No Allowance Recorded	37	46	38	48
Interest Income
With No Allowance Recorded	0		0	0
Less Than 35% LTV \| Real Estate \| Commercial \| Substandard
Average Recorded Investment
With No Allowance Recorded	40	0	26	0
Interest Income
With No Allowance Recorded	2		2
Less Than 35% LTV \| Real Estate \| Multifamily \| Substandard
Average Recorded Investment
With No Allowance Recorded	40	45	40	80
Interest Income
With No Allowance Recorded	0	1	1	1
Equal to or Greater than 35% LTV \| Real Estate \| Commercial \| Pass
Average Recorded Investment
With No Allowance Recorded	4,560	5,801	4,901	5,844
With a Related Allowance Recorded	659	0	439	0
Interest Income
With No Allowance Recorded	60	79	108	158
With a Related Allowance Recorded	17		33	0
Equal to or Greater than 35% LTV \| Real Estate \| Commercial \| Special Mention
Average Recorded Investment
With No Allowance Recorded	256	0	170	0
Interest Income
With No Allowance Recorded	10		20	0
Equal to or Greater than 35% LTV \| Real Estate \| Commercial \| Substandard
Average Recorded Investment
With No Allowance Recorded	9,666	10,979	9,923	11,373
With a Related Allowance Recorded	1,676	1,171	1,553	781
Interest Income
With No Allowance Recorded	119	57	156	129
With a Related Allowance Recorded	24	17	24	17
Equal to or Greater than 35% LTV \| Real Estate \| Multifamily \| Pass
Average Recorded Investment
With No Allowance Recorded	11	34	16	35
Interest Income
With No Allowance Recorded	0	4	0	8
Equal to or Greater than 35% LTV \| Real Estate \| Multifamily \| Special Mention
Average Recorded Investment
With No Allowance Recorded	11	0	7	0
Interest Income
With No Allowance Recorded	4		8	0
Equal to or Greater than 35% LTV \| Real Estate \| Multifamily \| Substandard
Average Recorded Investment
With No Allowance Recorded	792	1,100	852	1,143
Interest Income
With No Allowance Recorded	14	16	22	35
Less Than 60% LTV \| Real Estate \| One-to-Four Family \| Pass
Average Recorded Investment
With No Allowance Recorded	1,210	1,812	1,266	1,719
Interest Income
With No Allowance Recorded	13	22	29	44
Less Than 60% LTV \| Real Estate \| One-to-Four Family \| Special Mention
Average Recorded Investment
With No Allowance Recorded	380	0	382	0
Interest Income
With No Allowance Recorded	5		11	0
Less Than 60% LTV \| Real Estate \| One-to-Four Family \| Substandard
Average Recorded Investment
With No Allowance Recorded	387	238	446	239
With a Related Allowance Recorded	261	345	174	449
Interest Income
With No Allowance Recorded	3	1	9	4
With a Related Allowance Recorded	5	5	10	10
Equal to or Greater than 60% LTV \| Real Estate \| One-to-Four Family \| Pass
Average Recorded Investment
With No Allowance Recorded	119	126	120	127
Interest Income
With No Allowance Recorded	1	1	2	2
Equal to or Greater than 60% LTV \| Real Estate \| One-to-Four Family \| Substandard
Average Recorded Investment
With No Allowance Recorded	26	124	27	125
Interest Income
With No Allowance Recorded	$ 0	$ 3	$ 0	$ 6

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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-Publisher FASB
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-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

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