CREDIT QUALITY ASSESSMENT - Loans Modified (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 118,865	$ 61,861
% of total loan segment	1.00%	0.50%
Commercial Real Estate \| Commercial Investor R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 70,711	$ 52,308
% of total loan segment	1.50%	1.00%
Interest rate reduction, Weighted Average	0.90%	1.50%
Term extension, Weighted Average	8 months	15 months
Commercial Real Estate \| Commercial Owner- Occupied R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 13,682	$ 2,808
% of total loan segment	0.80%	0.20%
Interest rate reduction, Weighted Average	1.10%	0.00%
Term extension, Weighted Average	20 months	14 months
Commercial Real Estate \| Commercial AD&C
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 23,840	$ 1,016
% of total loan segment	1.80%	0.10%
Interest rate reduction, Weighted Average	0.00%	0.00%
Term extension, Weighted Average	6 months	9 months
Commercial Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 10,111	$ 5,729
% of total loan segment	0.60%	0.40%
Interest rate reduction, Weighted Average	2.10%	0.30%
Term extension, Weighted Average	16 months	14 months
All Other loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 521	$ 0
% of total loan segment	0.00%	0.00%
Interest rate reduction, Weighted Average	0.00%	0.00%
Term extension, Weighted Average	18 months
Interest rate reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 5,335	$ 29,203
Interest rate reduction \| Commercial Real Estate \| Commercial Investor R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	485	28,970
Interest rate reduction \| Commercial Real Estate \| Commercial Owner- Occupied R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	4,834	0
Interest rate reduction \| Commercial Real Estate \| Commercial AD&C
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	0	0
Interest rate reduction \| Commercial Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	16	233
Interest rate reduction \| All Other loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	0	0
Term extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	104,916	19,098
Term extension \| Commercial Real Estate \| Commercial Investor R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	61,981	9,778
Term extension \| Commercial Real Estate \| Commercial Owner- Occupied R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	8,848	2,808
Term extension \| Commercial Real Estate \| Commercial AD&C
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	23,840	1,016
Term extension \| Commercial Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	9,726	5,496
Term extension \| All Other loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	521	0
Rate reduction & Term extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	8,614	13,560
Rate reduction & Term extension \| Commercial Real Estate \| Commercial Investor R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	8,245	13,560
Rate reduction & Term extension \| Commercial Real Estate \| Commercial Owner- Occupied R/E
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	0	0
Rate reduction & Term extension \| Commercial Real Estate \| Commercial AD&C
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	0	0
Rate reduction & Term extension \| Commercial Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	369	0
Rate reduction & Term extension \| All Other loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amount	$ 0	$ 0

SANDY SPRING BANCORP INC 10-K