Regulatory Matters (Company's and Bank's actual capital amounts and ratios) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Capital to risk-weighted assets Company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Actual Amount	$ 511,845,000	$ 491,239,000
Actual Amount	474,042,000	452,473,000
Actual Amount	474,042,000	452,473,000
Actual Ratio	15.06%	15.65%
Actual Ratio	13.95%	14.42%
Actual Ratio	11.26%	11.32%
For Capital Adequacy Purposes Amount	271,925,000	251,060,000
For Capital Adequacy Purposes Amount	135,962,000	125,530,000
For Capital Adequacy Purposes Amount	126,261,000	119,939,000
For Capital Adequacy Purposes Ratio	8.00%	8.00%
For Capital Adequacy Purposes Ratio	4.00%	4.00%
For Capital Adequacy Purposes Ratio	3.00%	3.00%
Sandy Spring Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Actual Amount	497,832,000	478,023,000
Actual Amount	425,029,000	404,258,000
Actual Amount	425,029,000	404,258,000
Actual Ratio	14.66%	15.25%
Actual Ratio	12.52%	12.89%
Actual Ratio	10.11%	10.12%
For Capital Adequacy Purposes Amount	271,676,000	250,817,000
For Capital Adequacy Purposes Amount	135,838,000	125,408,000
For Capital Adequacy Purposes Amount	126,152,000	119,866,000
For Capital Adequacy Purposes Ratio	8.00%	8.00%
For Capital Adequacy Purposes Ratio	4.00%	4.00%
For Capital Adequacy Purposes Ratio	3.00%	3.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	339,595,000	313,521,000
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	203,757,000	188,112,000
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 210,254,000	$ 199,777,000
To Be Well Capitalized Under Prompt Action Provisions Ratio	10.00%	10.00%
To Be Well Capitalized Under Prompt Action Provisions Ratio	6.00%	6.00%
To Be Well Capitalized Under Prompt Action Provisions Ratio	5.00%	5.00%