Loans Receivable and Allowances - Impaired Loans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Real estate acquired through foreclosure	$ 1,010,000		$ 1,010,000		$ 1,010,000
Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, with no related allowance	6,586,000		6,586,000		7,432,000
Recorded investment, with no related allowance	6,150,000		6,150,000		7,152,000
Unpaid principal balance, with a related allowance	0		0		3,104,000
Recorded investment, with a related allowance	0		0		2,979,000
Related allowance					542,000
Unpaid principal balance	6,586,000		6,586,000		10,536,000
Recorded investment	6,150,000		6,150,000		10,131,000
Average recorded investment, with no related allowance	6,185,000	$ 8,835,000	6,254,000	$ 8,860,000
Interest income recognized, with no related allowance	85,000	53,000	178,000	133,000
Average recorded investment, with a related allowance		3,939,000		3,951,000
Interest income recognized, with a related allowance		30,000		78,000
Average recorded investment	6,185,000	12,774,000	6,254,000	12,811,000
Interest income recognized	85,000	83,000	178,000	211,000
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, with no related allowance	0		0		0
Recorded investment, with no related allowance	0		0		0
Unpaid principal balance, with a related allowance	0		0		0
Recorded investment, with a related allowance	0		0		0
Related allowance	0		0		0
Unpaid principal balance	0		0		0
Recorded investment	0		0		0
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, with no related allowance	628,000		628,000		548,000
Recorded investment, with no related allowance	624,000		624,000		547,000
Unpaid principal balance, with a related allowance	0		0		0
Recorded investment, with a related allowance	0		0		0
Related allowance					0
Unpaid principal balance	628,000		628,000		548,000
Recorded investment	624,000		624,000		547,000
Average recorded investment, with no related allowance	625,000	733,000	629,000	735,000
Interest income recognized, with no related allowance	12,000	5,000	20,000	20,000
Average recorded investment, with a related allowance		544,000		547,000
Interest income recognized, with a related allowance		11,000		19,000
Average recorded investment	625,000	1,277,000	629,000	1,282,000
Interest income recognized	12,000	16,000	20,000	39,000
ADC
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, with no related allowance	197,000		197,000		212,000
Recorded investment, with no related allowance	188,000		188,000		206,000
Unpaid principal balance, with a related allowance	100,000		100,000		102,000
Recorded investment, with a related allowance	100,000		100,000		102,000
Related allowance	29,000		29,000		29,000
Unpaid principal balance	297,000		297,000		314,000
Recorded investment	288,000		288,000		308,000
Average recorded investment, with no related allowance	192,000	225,000	196,000	230,000
Interest income recognized, with no related allowance	3,000	2,000	6,000	6,000
Average recorded investment, with a related allowance	100,000	104,000	101,000	104,000
Interest income recognized, with a related allowance	1,000		3,000	1,000
Average recorded investment	292,000	329,000	297,000	334,000
Interest income recognized	4,000	2,000	9,000	7,000
Home Equity/2nds Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, with no related allowance	939,000		939,000		910,000
Recorded investment, with no related allowance	513,000		513,000		491,000
Unpaid principal balance, with a related allowance	0		0		0
Recorded investment, with a related allowance	0		0		0
Related allowance	0		0		0
Unpaid principal balance	939,000		939,000		910,000
Recorded investment	513,000		513,000		491,000
Average recorded investment, with no related allowance	337,000	337,000	344,000	345,000
Interest income recognized, with no related allowance	8,000	8,000	16,000	15,000
Average recorded investment	337,000	337,000	344,000	345,000
Interest income recognized	8,000	8,000	16,000	15,000
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance, with no related allowance	61,000		61,000		63,000
Recorded investment, with no related allowance	61,000		61,000		63,000
Unpaid principal balance, with a related allowance	0		0		0
Recorded investment, with a related allowance	0		0		0
Related allowance	0		0		0
Unpaid principal balance	61,000		61,000		63,000
Recorded investment	61,000		61,000		63,000
Average recorded investment, with no related allowance	219,000	65,000	220,000	82,000
Interest income recognized, with no related allowance	2,000	1,000	5,000	2,000
Average recorded investment	219,000	65,000	220,000	82,000
Interest income recognized	2,000	$ 1,000	5,000	$ 2,000
Real estate acquired through foreclosure	0		0		0
Mortgage Loans in Process of Foreclosure, Amount	$ 124,000		$ 124,000		$ 3,600,000

SEVERN BANCORP INC 10-Q