ACQUISITION OF WASHINGTONFIRST BANKSHARES, INC	12 Months Ended
Dec. 31, 2017
Pending Business Combination [Abstract]
Business Combination Pending [Text Block]	Note 25 – acquisition of Washingtonfirst bankshares, inc. On January 1, 2018 (“Acquisition Date”), the Company completed its acquisition of WashingtonFirst Bankshares, Inc. (“WashingtonFirst”) in a transaction valued at approximately $452 million in the aggregate, based on the Company’s volume-weighted average share price of $39.5051. Volume-weighted average share price represents a volume-weighted average price of the Company’s common stock on the Nasdaq Global Select Market, for the twenty trading day period ending on the fifth trading day before the closing of the acquisition. As of the Acquisition Date, WashingtonFirst was merged into the Company and WashingtonFirst’s wholly-owned subsidiary, WashingtonFirst Bank, was merged with and into Sandy Spring Bank. The Company issued an aggregate of 11,446,441 shares of the Company’s common stock in the transaction. At the effective date of the acquisition, Sandy Spring shareholders owned approximately 67.7% of the combined company and WashingtonFirst’s shareholders owned approximately 32.3% of the combined company. WashingtonFirst was headquartered in Reston, Virginia, had 19 community banking offices throughout the Washington D.C. metropolitan region and more than $2.1 billion in assets as of December 31, 2017. In addition, WashingtonFirst provided wealth management services through its subsidiary, 1st Portfolio Wealth Advisors, and mortgage banking services through the bank’s subsidiary, WashingtonFirst Mortgage Corporation. The acquisition of WashingtonFirst is being accounted for as a business combination using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed, and consideration paid are recorded at estimated fair values on the Acquisition Date. Due to complexity of the fair value analysis and relatively short time frame between the Acquisition Date and financial statements issuance date, the valuation of acquired assets and assumed liabilities was not final as of the financial statements issuance date. The provisional amount of goodwill recognized was approximately $264 million. The estimated fair values of the acquired assets and assumed liabilities will be subject to refinement as additional information relative to closing date fair values becomes available. Any subsequent adjustments to the fair values of acquired assets and liabilities assumed, identifiable intangible assets, or other purchase accounting adjustments will result in adjustments to goodwill within the first 12 months following the closing date of acquisition. We anticipate to finalize the valuation by the end of the first quarter of 2018.

Note 25 – acquisition of Washingtonfirst bankshares, inc.

On January 1, 2018 (“Acquisition Date”), the Company completed its acquisition of WashingtonFirst Bankshares, Inc. (“WashingtonFirst”) in a transaction valued at approximately $452 million in the aggregate, based on the Company’s volume-weighted average share price of $39.5051. Volume-weighted average share price represents a volume-weighted average price of the Company’s common stock on the Nasdaq Global Select Market, for the twenty trading day period ending on the fifth trading day before the closing of the acquisition. As of the Acquisition Date, WashingtonFirst was merged into the Company and WashingtonFirst’s wholly-owned subsidiary, WashingtonFirst Bank, was merged with and into Sandy Spring Bank.

The Company issued an aggregate of 11,446,441 shares of the Company’s common stock in the transaction. At the effective date of the acquisition, Sandy Spring shareholders owned approximately 67.7% of the combined company and WashingtonFirst’s shareholders owned approximately 32.3% of the combined company.

WashingtonFirst was headquartered in Reston, Virginia, had 19 community banking offices throughout the Washington D.C. metropolitan region and more than $2.1 billion in assets as of December 31, 2017. In addition, WashingtonFirst provided wealth management services through its subsidiary, 1st Portfolio Wealth Advisors, and mortgage banking services through the bank’s subsidiary, WashingtonFirst Mortgage Corporation.

The acquisition of WashingtonFirst is being accounted for as a business combination using the acquisition method of accounting and, accordingly, assets acquired, liabilities assumed, and consideration paid are recorded at estimated fair values on the Acquisition Date. Due to complexity of the fair value analysis and relatively short time frame between the Acquisition Date and financial statements issuance date, the valuation of acquired assets and assumed liabilities was not final as of the financial statements issuance date. The provisional amount of goodwill recognized was approximately $264 million. The estimated fair values of the acquired assets and assumed liabilities will be subject to refinement as additional information relative to closing date fair values becomes available. Any subsequent adjustments to the fair values of acquired assets and liabilities assumed, identifiable intangible assets, or other purchase accounting adjustments will result in adjustments to goodwill within the first 12 months following the closing date of acquisition. We anticipate to finalize the valuation by the end of the first quarter of 2018.