Employee Stock Ownership Plan Employee Stock Ownership Plan (Narrative) (Details) - USD ($)		9 Months Ended
	Jul. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Jul. 21, 2015
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Stock Issued During Period, Shares, Employee Stock Ownership Plan		25,862	21,620
Stock Issued During Period, Value, Employee Stock Ownership Plan		$ 428,000	$ 256,000
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares		155,960	186,713	181,822
Summit Financial Group Inc. Employee Stock Ownership Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee Stock Ownership Plan (ESOP), Debt Structure, Indirect Loan, Amount					$ 2,250,000
Stock Issued During Period, Shares, Employee Stock Ownership Plan	225,000
Employee Stock Ownership Plan (ESOP), Weighted Average Purchase Price of Shares Purchased	$ 10.80
Stock Issued During Period, Value, Employee Stock Ownership Plan	$ 2,430,000
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares					208,333