Condensed Financial Statements Of Parent Company (Schedule Of Condensed Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Condensed Financial Statements, Captions [Line Items]
Securities available for sale	$ 281,539	$ 286,599
Premises and equipment	21,129	22,084
Accrued interest receivable	5,621	5,784
Cash surrender value of life insurance policies	29,553	29,284
Other assets	17,936	16,427
Total assets	1,387,104	1,450,121
Short-term borrowings	3,958	15,956
Long-term borrowings	203,268	270,254
Subordinated debentures	16,800	16,800		6,800	10,000
Subordinated debentures owed to unconsolidated subsidiary trusts	19,589	19,589
Other liabilities	7,809	8,456
Total liabilities	1,278,549	1,347,555
Preferred stock, value issued		5,807
Common stock and related surplus - authorized 20,000,000 shares; $2.50 par value; issued and outstanding 7,425,472 shares	24,520	24,518
Retained earnings	69,841	64,904
Accumulated other comprehensive income	4,868	3,818
Total shareholders' equity	108,555	102,566	89,821	90,660
Total liabilities and shareholders' equity	1,387,104	1,450,121
Summit Financial Group, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	5,495	8,466	4,608	7,164
Investment in subsidiaries, eliminated in consolidation	148,951	141,098
Securities available for sale	422	92
Premises and equipment		12
Accrued interest receivable	3	2
Cash surrender value of life insurance policies	44	43
Other assets	1,502	1,425
Total assets	156,417	151,138
Long-term borrowings	8,575	9,929
Subordinated debentures	16,800	16,800
Subordinated debentures owed to unconsolidated subsidiary trusts	19,589	19,589
Other liabilities	2,898	2,254
Total liabilities	47,862	48,572
Common stock and related surplus - authorized 20,000,000 shares; $2.50 par value; issued and outstanding 7,425,472 shares	24,520	24,518
Retained earnings	69,841	64,904
Accumulated other comprehensive income	4,868	3,818
Total shareholders' equity	108,555	102,566
Total liabilities and shareholders' equity	156,417	151,138
Series 2009 Preferred Stock And Related Surplus [Member]
Condensed Financial Statements, Captions [Line Items]
Preferred stock, value issued	3,519	3,519
Total shareholders' equity	3,519	3,519	3,519	3,519
Series 2009 Preferred Stock And Related Surplus [Member] | Summit Financial Group, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Preferred stock, value issued	3,519	3,519
Series 2011 Preferred Stock And Related Surplus [Member]
Condensed Financial Statements, Captions [Line Items]
Preferred stock, value issued	5,807	5,807
Total shareholders' equity	5,807	5,807
Series 2011 Preferred Stock And Related Surplus [Member] | Summit Financial Group, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Preferred stock, value issued	$ 5,807	$ 5,807