Loans - Average Recorded Investment and Interest Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Average Recorded Investment
Total	$ 19,687	$ 21,708	$ 20,211	$ 21,821
Interest Income
Total	110	182	546	598
Real Estate \| Commercial
Average Recorded Investment
Total	16,730	17,987	16,929	17,869
Interest Income
Total	76	132	419	436
Real Estate \| One-to-Four Family
Average Recorded Investment
Total	2,181	2,555	2,323	2,620
Interest Income
Total	23	33	85	98
Real Estate \| Multifamily
Average Recorded Investment
Total	672	1,045	853	1,206
Interest Income
Total	10	17	40	61
Real Estate \| Home equity and lines of credit
Average Recorded Investment
Total	50	57	51	59
Interest Income
Total	1	0	2	2
Real Estate \| Home equity and lines of credit \| Substandard
Average Recorded Investment
With a Related Allowance Recorded	32	33	32	33
Interest Income
With a Related Allowance Recorded	0		1	1
Real Estate \| Home equity and lines of credit \| Pass
Average Recorded Investment
With No Allowance Recorded	18	24	19	26
Interest Income
With No Allowance Recorded	1	0	1	1
Commercial and Industrial
Average Recorded Investment
Total	54	64	55	67
Interest Income
Total	0	0	0	1
Commercial and Industrial \| Substandard
Average Recorded Investment
With No Allowance Recorded	37	44	38	47
Interest Income
With No Allowance Recorded	0		0	0
Commercial and Industrial \| Special Mention
Average Recorded Investment
With a Related Allowance Recorded	17	20	17	20
Interest Income
With a Related Allowance Recorded	0		0	1
Less Than 35% LTV \| Real Estate \| Commercial \| Substandard
Average Recorded Investment
With No Allowance Recorded	79	0	40	0
Interest Income
With No Allowance Recorded	0		2
Less Than 35% LTV \| Real Estate \| Multifamily \| Substandard
Average Recorded Investment
With No Allowance Recorded	40	41	40	71
Interest Income
With No Allowance Recorded	0	0	1	1
Equal to or Greater than 35% LTV \| Real Estate \| Commercial \| Substandard
Average Recorded Investment
With No Allowance Recorded	8,440	10,707	9,550	11,156
With a Related Allowance Recorded	2,790	1,566	1,860	912
Interest Income
With No Allowance Recorded	3	54	159	183
With a Related Allowance Recorded	10	0	34	17
Equal to or Greater than 35% LTV \| Real Estate \| Commercial \| Pass
Average Recorded Investment
With No Allowance Recorded	3,607	5,714	4,572	5,801
With a Related Allowance Recorded	1,307	0	654	0
Interest Income
With No Allowance Recorded	37	78	145	236
With a Related Allowance Recorded	16		49	0
Equal to or Greater than 35% LTV \| Real Estate \| Commercial \| Special Mention
Average Recorded Investment
With No Allowance Recorded	507	0	253	0
Interest Income
With No Allowance Recorded	10		30	0
Equal to or Greater than 35% LTV \| Real Estate \| Multifamily \| Substandard
Average Recorded Investment
With No Allowance Recorded	611	974	791	1,101
Interest Income
With No Allowance Recorded	6	13	28	48
Equal to or Greater than 35% LTV \| Real Estate \| Multifamily \| Pass
Average Recorded Investment
With No Allowance Recorded	0	30	12	34
Interest Income
With No Allowance Recorded	0	4	0	12
Equal to or Greater than 35% LTV \| Real Estate \| Multifamily \| Special Mention
Average Recorded Investment
With No Allowance Recorded	21	0	10	0
Interest Income
With No Allowance Recorded	4		11	0
Less Than 60% LTV \| Real Estate \| One-to-Four Family \| Substandard
Average Recorded Investment
With No Allowance Recorded	474	233	517	236
With a Related Allowance Recorded	261	342	131	422
Interest Income
With No Allowance Recorded	8	4	27	8
With a Related Allowance Recorded	0	5	0	14
Less Than 60% LTV \| Real Estate \| One-to-Four Family \| Pass
Average Recorded Investment
With No Allowance Recorded	929	1,599	1,150	1,638
Interest Income
With No Allowance Recorded	9	16	38	49
Less Than 60% LTV \| Real Estate \| One-to-Four Family \| Special Mention
Average Recorded Investment
With No Allowance Recorded	376	195	380	97
Interest Income
With No Allowance Recorded	5	6	16	17
Equal to or Greater than 60% LTV \| Real Estate \| One-to-Four Family \| Substandard
Average Recorded Investment
With No Allowance Recorded	24	62	26	101
Interest Income
With No Allowance Recorded	0	1	1	7
Equal to or Greater than 60% LTV \| Real Estate \| One-to-Four Family \| Pass
Average Recorded Investment
With No Allowance Recorded	117	124	119	126
Interest Income
With No Allowance Recorded	$ 1	$ 1	$ 3	$ 3

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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-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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