Parent Only Financial Information Parent Only Statement of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Cash Flows from Operating Activities:
Net Income	$ 21,795		$ 22,179		$ 21,933
Net Gains on the Sale of Securities Available-for-Sale	527		949		2,795
Shares Issued Under the Directors' Stock Plan	(198)		(175)		(175)
Stock-Based Compensation Expense	372		424		354
Net Cash Provided By Operating Activities	36,673		32,460		36,085
Cash Flows from Investing Activities:
Proceeds from the Sale of Securities Available-for-Sale	16,295		58,718		39,009
Purchases of Securities Available-for-Sale	(136,416)		(197,029)		(354,310)
Net Cash Provided by (Used In) Investing Activities	(149,015)		(65,645)		(44,796)
Cash Flows from Financing Activities:
Shares Issued for Stock Options Exercised, net	1,254		2,105		1,413
Shares Issued Under the Employee Stock Purchase Plan	477		484		474
Shares Issued for Dividend Reinvestment Plans	1,280		1,822		1,796
Tax Benefit for Exercises of Stock Options	23		68		51
Purchases of Treasury Stock	(1,709)		(4,877)		(6,039)
Cash Dividends Paid	(12,109)	[1]	(11,815)	[1]	(11,448)	[1]
Net Cash Provided By Financing Activities	113,490		38,281		21,368
Net Increase in Cash and Cash Equivalents	1,148		5,096		12,657
Cash and Cash Equivalents at Beginning of Year	48,832		43,736		31,079
Cash and Cash Equivalents at End of Year	49,980		48,832		43,736
Interest on Deposits and Borrowings	8,067		12,520		19,490
Shares Issued for Acquisition of Subsidiary	233		233		5,261
Arrow Financial Corporation [Member]
Cash Flows from Operating Activities:
Net Income	21,795		22,179		21,933
Undistributed Net Income of Subsidiaries	(9,155)		(9,666)		(7,847)
Net Gains on the Sale of Securities Available-for-Sale	0		(63)		(17)
Shares Issued Under the Directors' Stock Plan	198		175		175
Stock-Based Compensation Expense	372		424		354
Changes in Other Assets and Other Liabilities	(990)		(1,640)		(165)
Net Cash Provided By Operating Activities	12,220		11,409		14,433
Cash Flows from Investing Activities:
Proceeds from the Sale of Securities Available-for-Sale	45		681		410
Purchases of Securities Available-for-Sale	(45)		(359)		(253)
Net Cash Provided by (Used In) Investing Activities	0		322		157
Cash Flows from Financing Activities:
Shares Issued for Stock Options Exercised, net	1,254		2,105		1,413
Shares Issued Under the Employee Stock Purchase Plan	477		484		474
Shares Issued for Dividend Reinvestment Plans	1,280		1,822		1,796
Tax Benefit for Exercises of Stock Options	23		68		51
Purchases of Treasury Stock	(1,709)		(4,877)		(6,039)
Cash Dividends Paid	(12,109)		(11,815)		(11,448)
Net Cash Provided By Financing Activities	(10,784)		(12,213)		(13,753)
Net Increase in Cash and Cash Equivalents	1,436		(482)		837
Cash and Cash Equivalents at Beginning of Year	1,913		2,395		1,558
Cash and Cash Equivalents at End of Year	3,349		1,913		2,395
Interest on Deposits and Borrowings	640		692		669
Shares Issued for Acquisition of Subsidiary	$ 233		$ 233		$ 5,261

[1] Cash dividends paid per share have been adjusted for the September 2013 2% stock dividend.