Arrow Financial (AROW) 10-K 13 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 27, 2015	Jun. 30, 2014
Entity Information [Line Items]
Entity Registrant Name	Arrow Financial Corporation
Entity Central Index Key	717538
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		12,625,734
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$319,738,450

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS
Cash and Due from Banks	$35,081	$37,275
Interest-Bearing Deposits at Banks	11,214	12,705
Investment Securities:
Available-for-sale Securities	366,139	457,606
Held-to-Maturity Securities	302,024	299,261
Federal Home Loan Bank and Federal Reserve Bank Stock	4,851	6,281
Loans	1,413,268	1,266,472
Allowance for Loan Losses	-15,570	-14,434
Net Loans	1,397,698	1,252,038
Premises and Equipment, Net	28,488	29,154
Goodwill	22,003	22,003
Other Intangible Assets, Net	3,625	4,140
Other Assets	46,297	43,235
Total Assets	2,217,420	2,163,698
LIABILITIES
Noninterest-Bearing Deposits	300,786	278,958
NOW Accounts	871,671	817,366
Savings Deposits	524,648	498,779
Time Deposits of $100,000 or More	61,797	78,928
Other Time Deposits	144,046	168,299
Total Deposits	1,902,948	1,842,330
Short-term Borrowings	60,421	64,777
Federal Home Loan Bank Term Advances	10,000	20,000
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	20,000	20,000
Other Liabilities	23,125	24,437
Total Liabilities	2,016,494	1,971,544
STOCKHOLDERS' EQUITY
Preferred Stock	0	0
Common Stock	17,079	16,744
Additional Paid-in Capital	239,721	229,290
Retained Earnings	29,458	27,457
Unallocated ESOP Shares	-1,450	-1,800
Accumulated Other Comprehensive Loss	-7,166	-4,373
Treasury Stock	-76,716	-75,164
Total Stockholders' Equity	200,926	192,154
Total Liabilities and Stockholders' Equity	$2,217,420	$2,163,698

Balance_Sheet_Parenthetical_Pa

Balance Sheet Parenthetical (Parentheticals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Held-to-maturity Securities, at Fair Value	$308,566	$302,305
Preferred Stock, Par Value	$5	$5
Preferred Stock, Shares Authorized	1,000,000	1,000,000
Common Stock, Par Value	$1	$1
Common Stock, Shares Authorized	20,000,000	20,000,000
Common Stock, Shares Issued	17,079,376	16,744,486
Unallocated ESOP Shares - Shares	71,748	87,641
Treasury Stock, Shares	4,386,022	4,296,723

Consolidated_Income_Statement

Consolidated Income Statement (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
INTEREST AND DIVIDEND INCOME
Interest and Fees on Loans	$53,194	$51,319		$54,511
Interest on Deposits at Banks	80	89		108
Interest and Dividends on Investment Securities:
Fully Taxable	7,954	6,903		9,269
Exempt from Federal Taxes	5,633	5,827		5,491
Total Interest and Dividend Income	66,861	64,138		69,379
INTEREST EXPENSE
NOW Accounts	1,722	2,461		3,564
Savings Deposits	839	1,024		1,287
Time Deposits of $100,000 or More	770	1,198		2,007
Other Time Deposits	1,354	1,962		3,730
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase	22	18		22
Federal Home Loan Bank Advances	490	680		729
Junior Subordinated Obligations Issued to Unconsolidated Subsidary Trusts	570	579		618
Total Interest Expense	5,767	7,922		11,957
NET INTEREST INCOME	61,094	56,216		57,422
Provision for Loan Losses	1,848	200		845
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	59,246	56,016		56,577
NONINTEREST INCOME
Income from Fiduciary Activities	7,468	6,735		6,290
Fees for Other Services to Customers	9,261	9,407		8,245
Insurance Commissions	9,455	8,895		8,247
Net Gains on Securities Transactions	110	540		865
Net Gains on Sale of Loans	784	1,460		2,282
Other Operating Income	1,238	1,024		1,170
Total Noninterest Income	28,316	28,061		27,099
NONINTEREST EXPENSE
Salaries and Employee Benefits	30,941	31,182		31,703
Occupancy Expense, Net	8,990	8,285		7,467
FDIC Assessments	1,117	1,080		1,026
Other Operating Expense	12,980	12,656		11,640
Total Noninterest Expense	54,028	53,203		51,836
INCOME BEFORE PROVISION FOR INCOME TAXES	33,534	30,874		31,840
Provision for Income Taxes	10,174	9,079		9,661
Net Income	$23,360	$21,795		$22,179
Average Shares Outstanding:
Basic Shares, in Shares	12,604	12,542	[1]	12,492	[1]
Diluted Shares, in Shares	12,633	12,573	[1]	12,502	[1]
Per Common Share
Basic Earnings, in Earnings Per Share	$1.85	$1.74	[1]	$1.78	[1]
Diluted Earnings, In Earnings Per Share	$1.85	$1.73	[1]	$1.77	[1]
[1]	Share and Per Share Amounts have been restated for the September 2014 2% stock dividend.

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Income	$23,360	$21,795	$22,179
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-2,961	3,500	-2,246
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	168	589	479
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	-2,793	4,089	-1,767
Comprehensive Income (Loss), Net of Tax	20,567	25,884	20,412
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	232	-2,925	-661
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-67	-326	-522
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-2,846	6,425	-1,340
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	288	914	1,013
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-347	0	-245
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	($53)	$1	($12)

Statement_of_Stockholders_Equi

Statement of Stockholders' Equity (USD $)		Total	Common Stock		Additional Paid in Capital	Retained Earnings	Unallocated ESOP Shares	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Stockholder's Equity Beginning Balance at Dec. 31, 2011		$166,385,000	$16,094,000		$207,600,000	$23,947,000	($2,500,000)	($6,695,000)	($72,061,000)
Net Income		22,179,000	0		0	22,179,000	0	0	0
Other Comprehensive (Loss) Income		-1,767,000	0		0	0	0	-1,767,000	0
Stock Dividend		0	322,000		7,738,000	-8,060,000	0	0	0
Cash Dividends Paid	[1]	-11,815,000	0		0	11,815,000	0	0	0
Stock Options Exercised		2,105,000	0		1,152,000	0	0	0	953,000
Shares Issued Under the Directors' Stock Plan		175,000	0		104,000	0	0	0	71,000
Shares Issued Under the Employee Stock Purchase Plan		484,000	0		279,000	0	0	0	205,000
Shares Issued for Dividend Reinvestment Plans		1,822,000	0		1,086,000	0	0	0	736,000
Stock-Based Compensation Expense		424,000	0		424,000	0	0	0	0
Tax Benefit for Disposition of Stock Options		68,000	0		68,000	0	0	0	0
Purchases of Treasury Stock		-4,877,000	0		0	0	0	0	-4,877,000
Shares Issued for Acquisition of Subsidiary		233,000	0		140,000	0	0	0	93,000
Allocation of ESOP Stock		409,000	0		-59,000	0	-350,000	0	0
Stockholder's Equity Ending Balance at Dec. 31, 2012		175,825,000	16,416,000		218,650,000	26,251,000	-2,150,000	-8,462,000	-74,880,000
Net Income		21,795,000	0		0	21,795,000	0	0	0
Other Comprehensive (Loss) Income		4,089,000	0		0	0	0	4,089,000	0
Stock Dividend		0	328,000		8,152,000	-8,480,000	0	0	0
Cash Dividends Paid	[1]	-12,109,000	0		0	12,109,000	0	0	0
Stock Options Exercised		1,254,000	0		676,000	0	0	0	578,000
Shares Issued Under the Directors' Stock Plan		198,000	0		123,000	0	0	0	75,000
Shares Issued Under the Employee Stock Purchase Plan		477,000	0		283,000	0	0	0	194,000
Shares Issued for Dividend Reinvestment Plans		1,280,000	0		796,000	0	0	0	484,000
Stock-Based Compensation Expense		372,000	0		372,000	0	0	0	0
Tax Benefit for Disposition of Stock Options		23,000	0		23,000	0	0	0	0
Purchases of Treasury Stock		-1,709,000	0		0	0	0	0	-1,709,000
Shares Issued for Acquisition of Subsidiary		233,000	0		139,000	0	0	0	94,000
Allocation of ESOP Stock		426,000	0		-76,000	0	-350,000	0	0
Stockholder's Equity Ending Balance at Dec. 31, 2013		192,154,000	16,744,000		229,290,000	27,457,000	-1,800,000	-4,373,000	-75,164,000
Net Income		23,360,000	0		0	23,360,000	0	0	0
Other Comprehensive (Loss) Income		-2,793,000	0		0	0	0	-2,793,000	0
Stock Dividend		0	335,000	[2]	8,617,000	-8,952,000	0	0	0
Cash Dividends Paid	[1]	-12,407,000	0		0	12,407,000	0	0	0
Stock Options Exercised		1,454,000	0		852,000	0	0	0	602,000
Shares Issued Under the Directors' Stock Plan		197,000	0		123,000	0	0	0	74,000
Shares Issued Under the Employee Stock Purchase Plan		488,000	0		296,000	0	0	0	192,000
Stock-Based Compensation Expense		360,000	0		360,000	0	0	0	0
Tax Benefit for Disposition of Stock Options		25,000	0		25,000	0	0	0	0
Purchases of Treasury Stock		-2,455,000	0		0	0	0	0	-2,455,000
Shares Issued for Acquisition of Subsidiary		91,000	0		56,000	0	0	0	35,000
Allocation of ESOP Stock		452,000	0		-102,000	0	-350,000	0	0
Stockholder's Equity Ending Balance at Dec. 31, 2014		$200,926,000	$17,079,000		$239,721,000	$29,458,000	($1,450,000)	($7,166,000)	($76,716,000)
[1]	Cash dividends paid per share have been adjusted for the September 2014 2% stock dividend.
[2]	Included in the shares issued for the 2% stock dividend in 2014 were treasury shares of 86,353 and unallocated ESOP shares of 1,407.

Stockholders_Equity_Parentheti

Stockholder's Equity Parenthetical (Parentheticals) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Dividends Paid, per Share	$0.99	$0.97	$0.95
Stock Dividends - Shares	334,890	328,323	321,886
Stock Options Exercised - Shares	61,364	58,719	96,471
Shares Issued Under Directors Stock Plan - Shares	7,584	7,643	7,226
Shares Issued Under the Employee Stock Purchase Plan - Shares	19,575	19,679	20,687
Shares Issued for Dividend Reinvestment Plans - Shares	0	49,574	74,260
Purchase of Treasury Stock - Shares	95,064	68,361	199,323
Acquisition of Subsidiary - Shares	3,595	9,503	9,356
Allocation of ESOP Stock - Shares	17,300	16,969	16,629

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Cash Flows from Operating Activities:
Net Income	$23,360		$21,795		$22,179
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Provision for Loan Losses	1,848		200		845
Depreciation and Amortization	7,042		8,870		8,856
Allocation of ESOP Stock	452		426		409
Gains on the Sale of Securities Available-for-Sale	-137		-527		-949
Held-to-maturity Securities, Sold Security, Realized Gain (Loss)	0		-18		0
Losses on the Sale of Securities Available-for-Sale	27		0		84
Held-to-Maturity Securities, Sold, Realized Loss	0		5		0
Loans Originated and Held-for-Sale	-23,156		-46,101		-60,668
Proceeds from the Sale of Loans Held-for-Sale	23,606		50,298		61,041
Net Gains on the Sale of Loans	-784		-1,460		-2,282
Net Loss (Gains) on the Sale of Premises and Equipment, Other Real Estate Owned and Repossessed Assets	77		120		-71
Contributions to Pension Plans	-921		-473		-328
Deferred Income Tax Expense (Benefit) Expense	-299		294		-353
Stock-Based Compensation Expense	197		198		175
Stock-Based Compensation Expense	360		372		424
Net Decrease in Other Assets	-806		1,888		2,108
Net Increase (Decrease) in Other Liabilities	-225		786		990
Net Cash Provided By Operating Activities	30,641		36,673		32,460
Cash Flows from Investing Activities:
Proceeds from the Sale of Securities Available-for-Sale	49,928		16,295		58,718
Proceeds from the Maturities and Calls of Securities Available-for-Sale	153,127		132,228		210,224
Purchases of Securities Available-for-Sale	-113,953		-136,416		-197,029
Proceeds from Sale and Maturity of Held-to-maturity Securities	0		1,181		0
Proceeds from the Maturities and Calls of Securities Held-to-Maturity	56,714		47,228		49,983
Purchases of Securities Held-to-Maturity	-60,906		-109,620		-140,635
Net (Increase) Decrease in Loans	-148,482		-98,903		-40,951
Proceeds from the Sales of Premises and Equipment, Other Real Estate Owned and Repossessed Assets	1,237		1,789		1,263
Purchases of Premises and Equipment	-1,468		-2,233		-8,073
Cash Paid for Subsidiaries	-75		-75		-75
Net Decrease (Increase) in Other Investments	1,430		-489		930
Purchase of Bank Owned Life Insurance	-5,245		0		0
Net Cash Used In Investing Activities	-67,693		-149,015		-65,645
Cash Flows from Financing Activities:
Net Increase in Deposits	60,618		111,175		87,109
Net (Decrease) Increase in Short-Term Borrowings	-4,356		23,099		-26,615
Federal Home Loan Bank Repayments	-10,000		-10,000		-10,000
Purchases of Treasury Stock	-2,455		-1,709		-4,877
Stock Options Exercised	1,454		1,254		2,105
Shares Issued Under the Employee Stock Purchase Plan	488		477		484
Tax Benefit from Exercise of Stock Options	25		23		68
Shares Issued for Dividend Reinvestment Plans	0		1,280		1,822
Cash Dividends Paid	-12,407	[1]	-12,109	[1]	-11,815	[1]
Net Cash Provided By Financing Activities	33,367		113,490		38,281
Net Increase (Decrease) in Cash and Cash Equivalents	-3,685		1,148		5,096
Cash and Cash Equivalents at Beginning of Year	49,980		48,832		43,736
Cash and Cash Equivalents at End of Year	46,295		49,980		48,832
Supplemental Disclosures to Statements of Cash Flow Information:
Interest on Deposits and Borrowings	5,932		8,067		12,520
Income Taxes	10,060		8,336		8,866
Non-cash Investing and Financing Activities:
Transfer of Loans to Other Real Estate Owned and Repossessed Assets	1,308		971		1,426
Shares Issued for Acquisition of Subsidiary	$91		$233		$233
[1]	Cash dividends paid per share have been adjusted for the September 2014 2% stock dividend.

Risks_and_Uncertainties

Risks and Uncertainties	12 Months Ended
	Dec. 31, 2014
Risks and Uncertainties [Abstract]
Concentration Risk Disclosure [Text Block]	RISKS AND UNCERTAINTIES
	Nature of Operations - Arrow Financial Corporation, a New York corporation, was incorporated on March 21, 1983 and is registered as a bank holding company within the meaning of the Bank Holding Company Act of 1956. Arrow derives most of its earnings from the ownership of two nationally chartered commercial banks and through the ownership of four insurance agencies. The two banks provide a full range of services to individuals and small to mid-size businesses in northeastern New York State from just north of Albany, the State's capitol, to the Canadian border. Both banks have trust departments which provide investment management and administrative services. The insurance agencies specialize in property and casualty insurance, group health insurance, sports accident and health insurance, and individual life insurance.
	Management’s Use of Estimates - The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of income and expenses during the reporting period.  Our most significant estimates are the allowance for loan losses, the evaluation of other-than-temporary impairment of investment securities, goodwill impairment, pension and other postretirement liabilities, analysis of a need for a valuation allowance for deferred tax assets and other fair value calculations. Actual results could differ from those estimates.
	A material estimate that is particularly susceptible to significant change in the near term is the allowance for loan losses.  The allowance for loan losses is management’s best estimate of probable loan losses incurred as of the balance sheet date.  While management uses available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on changes in economic conditions.
	Concentrations of Credit - Virtually all of Arrow's loans are with customers in upstate New York.  Although the loan portfolios of the subsidiary banks are well diversified, tourism has a substantial impact on the northeastern New York economy.  The commitments to extend credit are fairly consistent with the distribution of loans presented in Note 5, generally have the same credit risk and are subject to normal credit policies.  Generally, the loans are secured by assets and are expected to be repaid from cash flow or the sale of selected assets of the borrowers.  Arrow evaluates each customer's creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by Arrow upon extension of credit, is based upon management's credit evaluation of the counterparty.  The nature of the collateral varies with the type of loan and may include:  residential real estate, cash and securities, inventory, accounts receivable, property, plant and equipment, income producing commercial properties and automobiles.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Principles of Consolidation - The financial statements of Arrow and its wholly owned subsidiaries are consolidated and all material inter-company transactions have been eliminated.  In the “Parent Company Only” financial statements in Note 20, the investment in wholly owned subsidiaries is carried under the equity method of accounting.  When necessary, prior years’ consolidated financial statements have been reclassified to conform to the current-year financial statement presentation.
	The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity under GAAP. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. The Company consolidates voting interest entities in which it has all, or at least a majority of, the voting interest. As defined in applicable accounting standards, variable interest entities (VIE) are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when the Company has both the power and ability to direct the activities of the VIE that most significantly impact the VIE's economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Company’s wholly owned subsidiaries Arrow Capital Statutory Trust II and Arrow Capital Statutory Trust III are VIEs for which the Company is not the primary beneficiary. Accordingly, the accounts of these entities are not included in the Company’s consolidated financial statements.
	Segment Reporting - Arrow operations are primarily in the community banking industry, which constitutes Arrow’s only segment for financial reporting purposes.  Arrow provides other services, such as trust administration, retirement plan administration, advice to our proprietary mutual funds and insurance products, but these services do not rise to the quantitative thresholds for separate disclosure.  Arrow operates primarily in the northeastern region of New York State in Warren, Washington, Saratoga, Essex, Clinton and Albany counties and surrounding areas.
	Cash and Cash Equivalents - Cash and cash equivalents include the following items:  cash at branches, due from bank balances, cash items in the process of collection, interest-bearing bank balances and federal funds sold.
	Securities - Management determines the appropriate classification of securities at the time of purchase.  Securities reported as held-to-maturity are those debt securities which Arrow has both the positive intent and ability to hold to maturity and are stated at amortized cost.  Securities available-for-sale are reported at fair value, with unrealized gains and losses reported in accumulated other comprehensive income or loss, net of taxes.  Realized gains and losses are based upon the amortized cost of the specific security sold.  A decline in the fair value of any available-for-sale or held-to-maturity security below cost that is deemed to be other-than-temporary results in an impairment to reduce the carrying amount to fair value.  To determine whether an impairment is other-than-temporary, we consider all available information relevant to the collectibility of the security, including past events, current conditions, and reasonable and supportable forecasts when developing an estimate of cash flows expected to be collected.  Evidence considered in this assessment includes the reasons for impairment, the severity and duration of the impairment, changes in value subsequent to year-end, forecasted performance of the investee, and the general market condition in the geographic area or industry the investee operates in.  When an other-than-temporary impairment has occurred on a debt security, the amount of the other-than-temporary impairment recognized in earnings depends on whether we intend to sell the debt security or more likely than not will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss.  If we intend to sell the debt security or it is more likely than not that we will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss, the other-than-temporary impairment is recognized in earnings equal to the entire difference between the investment’s amortized cost basis and its fair value at the balance sheet date.  If we do not intend to sell the debt security and it is not more likely than not that we will be required to sell the debt security before recovery of its amortized cost basis, the other-than-temporary impairment is separated into the amount representing the credit loss and the amount related to all other factors.  The amount of the total other-than-temporary impairment related to the credit loss is recognized in earnings.  The amount of the total other-than-temporary impairment related to other factors is recognized in other comprehensive income, net of applicable income taxes.
	Loans and Allowance for Loan Losses - Interest income on loans is accrued and credited to income based upon the principal amount outstanding.  Loan fees and costs directly associated with loan originations are deferred and amortized/accreted as an adjustment to yield over the lives of the loans originated.
	From time-to-time, Arrow has sold (most with servicing retained) residential real estate loans at or shortly after origination.  Any gain or loss on the sale of loans, along with the value of the servicing right, is recognized at the time of sale as the difference between the recorded basis in the loan and net proceeds from the sale.  Loans held for sale are recorded at the lower of cost or fair value on an aggregate basis.
	Loans are placed on nonaccrual status either due to the delinquency status of principal and/or interest or a judgment by management that the full repayment of principal and interest is unlikely. Unless already placed on nonaccrual status, loans secured by home equity lines of credit are put on nonaccrual status when 120 days past due; residential real estate loans when 150 days past due; commercial and commercial real estate loans are evaluated on a loan-by-loan basis and are placed on nonaccrual status when 90 days past due if the full collection of principal and interest is uncertain. The balance of any accrued interest deemed uncollectible at the date the loan is placed on nonaccrual status is reversed, generally against interest income.  A loan is returned to accrual status at the later of the date when the past due status of the loan falls below the threshold for nonaccrual status or management deems that it is likely that the borrower will repay all interest and principal.  For payments received while the loan is on nonaccrual status, we may recognize interest income on a cash basis if the repayment of the remaining principal and accrued interest is deemed likely.
	The allowance for loan losses is maintained by charges to operations based upon our best estimate of the probable amount of loans that we will be unable to collect based on current information and events.  Provisions to the allowance for loan losses are offset by actual loan charge-offs (net of any recoveries).  We evaluate the loan portfolio for potential charge-offs on a monthly basis.  In general, automobile and other consumer loans are charged-off when 120 days delinquent.  Residential real estate loans are charged-off when a loss becomes known or based on a new appraisal at the earlier of 180 days past due or repossession.  Commercial and commercial real estate loans loans are evaluated early in their delinquency status and are charged-off when management concludes that not all principal will be repaid from on-going cash flows or liquidation of collateral. An evaluation of estimated proceeds from the liquidation of the loan’s collateral is compared to the loan carrying amount and a charge to the allowance for loan losses is taken for any deficiency.  While management uses available information to recognize losses on loans, future additions to the allowance may be necessary based on changes in economic conditions in Arrow's market area.  In addition, various Federal regulatory agencies, as an integral part of their examination process, review Arrow's allowance for loan losses. Such agencies may require Arrow to recognize additions to the allowance in future periods, based on their judgments about information available to them at the time of their examination, which may not be currently available to management.
	We consider nonaccrual loans over $250 thousand and all troubled debt restructured loans to be impaired loans and we evaluate these loans individually to determine the amount of impairment, if any. The amount of impairment, if any, related to individual impaired loans is measured based on either the present value of expected future cash flows discounted at the loan's effective interest rate, the loan's observable market price or the fair value of the collateral if the loan is collateral dependent. Arrow determines impairment for collateral dependent loans based on the fair value of the collateral less estimated costs to sell. Any excess of the recorded investment in the collateral dependent impaired loan over the estimated collateral value, less costs to sell, is typically charged off. For impaired loans which are not collateral dependent, impairment is measured by comparing the recorded investment in the loan to the present value of the expected cash flows, discounted at the loan’s effective interest rate.  If this amount is less than the recorded investment in the loan, an impairment reserve is recognized as part of the allowance for loan losses, or based upon the judgment of management all or a portion of the excess of the recorded investment in the loan over the present value of the estimated future cash flow may be charged off.
	The allowance for loan losses on the remaining loans is primarily determined based upon consideration of the historical net loss experience of the respective portfolios that have occurred within each pool of loans over the loss emergence period (LEP), adjusted as necessary based upon consideration of qualitative considerations impacting the inherent risk of loss in the respective loan portfolios. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is recognized in the financial statements. Since the LEP may change under various economic environments, we update the LEP calculation on a semiannual basis.
	In management’s opinion, the balance of the allowance for loan losses, at each balance sheet date, is sufficient to provide for probable loan losses inherent in the corresponding loan portfolio.
	Other Real Estate Owned and Repossessed Assets - Real estate acquired by foreclosure and assets acquired by repossession are recorded at the fair value of the property less estimated costs to sell at the time of repossession.  Subsequent declines in fair value, after transfer to other real estate owned and repossessed assets are recognized through a valuation allowance. Such declines in fair value along with related operating expenses to administer such properties or assets are charged directly to operating expense.
	Premises and Equipment - Premises and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization included in operating expenses are computed largely on the straight-line method. Depreciation is based on the estimated useful lives of the assets (buildings and improvements 20-40 years; furniture and equipment 7-10 years; data processing equipment 5-7 years) and, in the case of leasehold improvements, amortization is computed over the terms of the respective leases or their estimated useful lives, whichever is shorter.  Gains or losses on disposition are reflected in earnings.
	Income Taxes - Arrow accounts for income taxes under the asset and liability method.  Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases.  Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income tax expense in the period that includes the enactment date.  Arrow’s policy is that deferred tax assets are reduced by a valuation allowance if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.
	Goodwill and Other Intangible Assets - Identifiable intangible assets acquired in a business combination are capitalized and amortized.  Any remaining unidentifiable intangible asset is classified as goodwill, for which amortization is not required but which must be evaluated for impairment.  Arrow tests for impairment of goodwill on an annual basis, or when events and circumstances indicate potential impairment.  In evaluating goodwill for impairment, Arrow first assesses certain qualitative factors to determine if it is more likely than not that the fair value of the reporting unit is less than its carrying value. If it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is considered not impaired. If the carrying amount of a reporting unit exceeds its fair value, the second step of the goodwill impairment test is performed to measure the amount of impairment loss, if any.
	The carrying amounts of other recognized intangible assets that meet recognition criteria and for which separate accounting records have been maintained (core deposit intangibles and mortgage servicing rights), have been included in the consolidated balance sheet as “Other Intangible Assets, Net.”  Core deposit intangibles are being amortized on a straight-line basis over a period of ten to fifteen years.
	Arrow has sold residential real estate loans, primarily to Freddie Mac, with servicing retained.   Mortgage servicing rights are recognized as an asset when loans are sold with servicing retained, by allocating the cost of an originated mortgage loan between the loan and servicing right based on estimated relative fair values.  The cost allocated to the servicing right is capitalized as a separate asset and amortized in proportion to, and over the period of, estimated net servicing income.  Capitalized mortgage servicing rights are evaluated for impairment by comparing the asset’s carrying value to its current estimated fair value.  Fair values are estimated using a discounted cash flow approach, which considers future servicing income and costs, current market interest rates, and anticipated prepayment, and default rates.  Impairment losses are recognized through a valuation allowance for servicing rights having a current fair value that is less than amortized cost on an aggregate basis.  Adjustments to increase or decrease the valuation allowance are charged or credited to income as a component of other operating income.
	Pension and Postretirement Benefits - Arrow maintains a non-contributory, defined benefit pension plan covering substantially all employees, a supplemental pension plan covering certain executive officers selected by the Board of Directors, and certain post-retirement medical, dental and life insurance benefits for employees and retirees.  The costs of these plans, based on actuarial computations of current and future benefits for employees, are charged to current operating expenses. The cost of post-retirement benefits other than pensions is recognized on an accrual basis as employees perform services to earn the benefits.  Arrow recognizes the overfunded or underfunded status of our single employer defined benefit pension plan as an asset or liability on its consolidated balance sheet and recognizes changes in the funded status in comprehensive income in the year in which the change occurred.
	Prior service costs or credits are amortized on a straight-line basis over the average remaining service period of active participants.  Gains and losses in excess of 10% of the greater of the benefit obligation or the fair value of assets are amortized over the average remaining service period of active participants.
	The discount rate assumption is determined by preparing an analysis of the respective plan’s expected future cash flows and high-quality fixed-income investments currently available and expected to be available during the period to maturity of the pension benefits.
	Stock-Based Compensation Plans - Arrow has two stock option plans, which are described more fully in Note 12.  The Company expenses the grant date fair value of options granted.  The expense is recognized over the vesting period of the grant, typically four years, on a straight-line basis. Shares are generally issued from treasury for the exercise of stock options.
	Arrow sponsors an Employee Stock Purchase Plan ("ESPP") under which employees may purchase Arrow’s common stock at a 5% discount below market price at the time of purchase. This stock purchase plan is not considered a compensatory plan.
	Arrow sponsors an Employee Stock Ownership Plan ("ESOP"), a qualified defined contribution plan.   The ESOP has borrowed funds from one of Arrow’s subsidiary banks to purchase Arrow common stock.  The shares pledged as collateral are reported as a reduction of Arrow’s stockholders’ equity.  Compensation expense is recognized as shares are released for allocation to individual employee accounts equal to the current average market price.
	Securities Sold Under Agreements to Repurchase - In securities repurchase agreements, Arrow receives cash from a counterparty in exchange for the transfer of securities to a third party custodian’s account that explicitly recognizes Arrow’s interest in the securities.  These agreements are accounted for by Arrow as secured financing transactions, since it maintains effective control over the transferred securities, and meets other criteria for such accounting.  Accordingly, the cash proceeds are recorded as borrowed funds, and the underlying securities continue to be carried in Arrow’s securities available-for-sale portfolio.
	Earnings Per Share (“EPS”) - Basic EPS excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period.  Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity (such as Arrow’s stock options), computed using the treasury stock method.  Unallocated common shares held by Arrow’s Employee Stock Ownership Plan are not included in the weighted average number of common shares outstanding for either the basic or diluted EPS calculation.
	Financial Instruments - Arrow is a party to certain financial instruments with off-balance sheet risk, such as:  commercial lines of credit, construction lines of credit, overdraft protection, home equity lines of credit and standby letters of credit.  Arrow's policy is to record such instruments when funded.  Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument.  These estimates do not reflect any premium or discount that could result from offering for sale at one time Arrow's entire holdings of a particular financial instrument.  Because no market exists for a significant portion of Arrow's financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors.  These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision.  Changes in assumptions could significantly affect the estimates.
	Fair value estimates are based on existing on- and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments.  For example, Arrow has a trust department that contributes net fee income annually.  The value of trust department customer relationships is not considered a financial instrument of the Company, and therefore this value has not been incorporated into the fair value estimates. Other significant assets and liabilities that are not considered financial assets or liabilities include deferred taxes, premises and equipment, the value of low-cost, long-term core deposits and goodwill.  In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in any of the estimates.
	The carrying amount of the following short-term assets and liabilities is a reasonable estimate of fair value: cash and due from banks, federal funds sold and purchased, securities sold under agreements to repurchase, demand deposits, savings, N.O.W. and money market deposits, other short-term borrowings, accrued interest receivable and accrued interest payable.  The fair value estimates of other on- and off-balance sheet financial instruments, as well as the method of arriving at fair value estimates, are included in the related footnotes and summarized in Note 17.
	Fair Value Measures - We determine the fair value of financial instruments under the following hierarchy:
	•	Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	•	Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability;
	•	Level 3 – Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement.
	Management’s Use of Estimates -The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of income and expenses during the reporting period.  Our most significant estimates are the allowance for loan losses, the evaluation of other-than-temporary impairment of investment securities, goodwill impairment, pension and other postretirement liabilities, analysis of a need for a valuation allowance for deferred tax assets and other fair value calculations. Actual results could differ from those estimates.
	A material estimate that is particularly susceptible to significant change in the near term is the allowance for loan losses.  In connection with the determination of the allowance for loan losses, management obtains appraisals for properties.  The allowance for loan losses is management’s best estimate of probable loan losses incurred as of the balance sheet date.  While management uses available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on changes in economic conditions.
	Recent Accounting Pronouncements
	During 2014 the FASB issued eighteen accounting standards updates and, through the date of this report, one additional update in 2015. For those updates that apply to Arrow, the following paragraphs provide a brief description, the effective date and the estimated impact on our financial condition or results of operations.
	ASU 2014-01 "Investments-Equity Method and Joint Ventures" allows an entity that invests in affordable housing projects that qualify for low-income housing tax credits to make an accounting policy election to account for their investments in qualified affordable housing projects using the proportional amortization method if certain conditions are met. Under the proportional amortization method, an entity amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense. The standard is effective for annual years beginning after December 15, 2014, with earlier adoption allowed. We are evaluating the impact of adopting this election and do not expect that this will have a material impact on our financial condition or results of operations.
	ASU 2014-04 "Receivables - Trouble Debt Restructurings by Creditors" provides additional guidance on when an in substance repossession or foreclosure occurs and is effective for annual periods beginning after December 15, 2014. We are evaluating the impact of adopting this standard, and we do not expect that it will have a material impact on our financial condition or results of operations.
	ASU 2014-14 "Receivables - Trouble Debt Restructurings by Creditors - Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure" requires an entity to report a separate other receivable for the amount of the expected guarantee upon foreclosure. For Arrow, the standard is effective for the first quarter of 2015. The adoption will not have a material impact on our financial condition or results of operations.
	ASU 2015-01 "Income Statement - Extraordinary and Unusual Items" eliminates the concept of extraordinary items.

Cash_and_Cash_Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents Disclosure [Text Block]	CASH AND CASH EQUIVALENTS (Dollars In Thousands)
	The following table is the schedule of cash and cash equivalents at December 31, 2014 and 2013:
		2014		2013
	Cash and Due From Banks	$	35,081	$	37,275
	Interest-Bearing Deposits at Banks	11,214		12,705
	Total Cash and Cash Equivalents	$	46,295	$	49,980
	Supplemental Information:
	Total required reserves, including vault cash and Federal Reserve Bank deposits	$	19,989	$	18,879
	The Company is required to maintain reserve balances with the Federal Reserve Bank of New York. The required reserve is calculated on a fourteen day average and the amounts presented in the table above represent the average for the period that includes December 31.

Investment_Securities

Investment Securities	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]
		INVESTMENT SECURITIES (Dollars In Thousands)
	The following table is the schedule of Available-For-Sale Securities at December 31, 2014 and 2013:
	Available-For-Sale Securities
			U.S. Agency			State and		Mortgage-		Corporate		Mutual Funds		Total
			Obligations			Municipal		Backed		and Other		and Equity		Available-
						Obligations		Securities -		Debt		Securities		For-Sale
								Residential		Securities				Securities
	December 31, 2014
	Available-For-Sale Securities,		$	137,540		$	81,582	$	124,732	$	16,988	$	1,120	$	361,962
	at Amortized Cost
	Available-For-Sale Securities,		137,603			81,730		128,827		16,725		1,254		366,139
	at Fair Value
	Gross Unrealized Gains		208			187		4,100		7		134		4,636
	Gross Unrealized Losses		145			39		5		270		—		459
	Available-For-Sale Securities,													267,384
	Pledged as Collateral
	Available-For-Sale Securities
			U.S. Agency			State and		Mortgage-		Corporate		Mutual Funds		Total
			Obligations			Municipal		Backed		and Other		and Equity		Available-
						Obligations		Securities -		Debt		Securities		For-Sale
								Residential		Securities				Securities
	Maturities of Debt Securities,
	at Amortized Cost:
	Within One Year		—			28,273		2,878		2,303				33,454
	From 1 - 5 Years		137,540			51,384		100,428		13,685				303,037
	From 5 - 10 Years		—			1,285		21,426		—				22,711
	Over 10 Years		—			640		—		1,000				1,640
	Maturities of Debt Securities,
	at Fair Value:
	Within One Year		—			28,329		2,888		2,307				33,524
	From 1 - 5 Years		137,603			51,476		103,786		13,618				306,483
	From 5 - 10 Years		—			1,285		22,153		—				23,438
	Over 10 Years		—			640		—		800				1,440
	Securities in a Continuous
	Loss Position, at Fair Value:
	Less than 12 Months		$	39,631		$	3,309	$	82	$	—	$	—	$	43,022
	12 Months or Longer		28,020			14,035		1,546		10,738		—		54,339
	Total		$	67,651		$	17,344	$	1,628	$	10,738	$	—	$	97,361
	Number of Securities in a		22			65		3		15		—		105
	Continuous Loss Position
	Unrealized Losses on
	Securities in a Continuous
	Loss Position:
	Less than 12 Months		$	48		$	—	$	—	$	—	$	—	$	48
	12 Months or Longer		97			39		5		270		—		411
	Total		$	145		$	39	$	5	$	270	$	—	$	459
	December 31, 2013
	Available-For-Sale Securities,		$	136,868		$	127,224	$	171,321	$	17,142	$	1,120	$	453,675
	at Amortized Cost
	Available-For-Sale Securities,		136,475			127,389		175,778		16,798		1,166		457,606
	at Fair Value
	Gross Unrealized Gains		2			306		4,714		10		46		5,078
	Gross Unrealized Losses		395			141		257		354		—		1,147
	Available-For-Sale Securities,													243,769
	Pledged as Collateral
	Securities in a Continuous
	Loss Position, at Fair Value:
	Less than 12 Months		$	60,664		$	29,967	$	15,190	$	7,375	$	—	$	113,196
	12 Months or Longer		33,849			4,597		11,841		6,063		—		56,350
	Total		$	94,513		$	34,564	$	27,031	$	13,438	$	—	$	169,546
	Number of Securities in a		26			107		13		19		—		165
	Continuous Loss Position
	Unrealized Losses on
Securities in a Continuous
Loss Position:
Less than 12 Months		$	336		$	120	$	108	$	92	$	—	$	656
12 Months or Longer		59			21		149		262		—		491
Total		$	395		$	141	$	257	$	354	$	—	$	1,147
The following table is the schedule of Held-To-Maturity Securities at December 31, 2014 and 2013:
Held-To-Maturity Securities
		State and			Mortgage-		Corporate		Total
		Municipal			Backed		and Other		Held-To
		Obligations			Securities -		Debt		Maturity
					Residential		Securities		Securities
December 31, 2014
Held-To-Maturity Securities,		$	188,472		$	112,552	$	1,000	$	302,024
at Amortized Cost
Held-To-Maturity Securities,		193,252			114,314		1,000		308,566
at Fair Value
Gross Unrealized Gains		4,935			1,770		—		6,705
Gross Unrealized Losses		155			8		—		163
Held-To-Maturity Securities,									282,640
Pledged as Collateral
Maturities of Debt Securities,
at Amortized Cost:
Within One Year		34,163			—		—		34,163
From 1 - 5 Years		88,866			36,649		—		125,515
From 5 - 10 Years		63,394			75,903		—		139,297
Over 10 Years		2,049			—		1,000		3,049
Maturities of Debt Securities,
at Fair Value:
Within One Year		34,236			—		—		34,236
From 1 - 5 Years		91,148			37,133		—		128,281
From 5 - 10 Years		65,728			77,181		—		142,909
Over 10 Years		2,140			—		1,000		3,140
Securities in a Continuous
Loss Position, at Fair Value:
Less than 12 Months		$	2,143		$	4,581	$	—	$	6,724
12 Months or Longer		16,033			—		—		16,033
Total		$	18,176		$	4,581	$	—	$	22,757
Number of Securities in a		74			1		—		75
Continuous Loss Position
Unrealized Losses on
Securities in a Continuous
Loss Position:
Less than 12 Months		$	17		$	8	$	—	$	25
12 Months or Longer		138			—		—		138
Total		$	155		$	8	$	—	$	163
December 31, 2013
Held-To-Maturity Securities,		$	198,206		$	100,055	$	1,000	$	299,261
at Amortized Cost
Held-To-Maturity Securities,		202,390			98,915		1,000		302,305
at Fair Value
Gross Unrealized Gains		4,762			24		—		4,786
Gross Unrealized Losses		578			1,164		—		1,742
Held-To-Maturity Securities,									298,261
Pledged as Collateral
Held-To-Maturity Securities
		State and			Mortgage-		Corporate		Total
		Municipal			Backed		and Other		Held-To
		Obligations			Securities -		Debt		Maturity
					Residential		Securities		Securities
Securities in a Continuous
Loss Position, at Fair Value:
Less than 12 Months		$	23,633		$	85,339	$	—	$	108,972
12 Months or Longer		5,111			—		—		5,111
Total		$	28,744		$	85,339	$	—	$	114,083
Number of Securities in a		101			36		—		137
Continuous Loss Position
Unrealized Losses on
Securities in a Continuous
Loss Position:
Less than 12 Months		$	519		$	1,164	$	—	$	1,683
12 Months or Longer		59			—		—		59
Total		$	578		$	1,164	$	—	$	1,742
In the tables above, maturities of mortgage-backed-securities - residential are included based on their expected average lives.  Actual maturities will differ from the table below because issuers may have the right to call or prepay obligations with or without prepayment penalties.
In the available-for-sale category at December 31, 2014, U.S. agency obligations consisted solely of U.S. Government Agency securities with an amortized cost of $137.5 million and a fair value of $137.6 million. Mortgage-backed securities-residential consisted of U.S. Government Agency securities with an amortized cost of $23.0 million and a fair value of $23.6 million and GSE securities with an amortized cost of $101.7 million and a fair value of $105.2 million. In the held-to-maturity category at December 31, 2014, mortgage-backed securities-residential consisted of U.S. Government Agency securities with an amortized cost of $4.4 million and a fair value of $4.5 million and GSE securities with an amortized cost of $108.1 million and a fair value of $109.8 million.
In the available-for-sale category at December 31, 2013, U.S. agency obligations consisted solely of U.S. Government Agency securities with an amortized cost of $136.9 million and a fair value of $136.5 million. Mortgage-backed securities-residential consisted of U.S. Government Agency securities with an amortized cost of $31.5 million and a fair value of $32.2 million and GSE securities with an amortized cost of $139.8 million and a fair value of $143.6 million. In the held-to-maturity category at December 31, 2013, mortgage-backed securities-residential consisted of GSEs with an amortized cost of $100.1 million and a fair value of $98.9 million.
Securities in a continuous loss position, in the tables above for December 31, 2014 and December 31, 2013 do not reflect any deterioration of the credit worthiness of the issuing entities.  U.S. agency issues, including mortgage-backed securities, are all rated Aaa by Moody's and AA+ by Standard and Poor's.  The state and municipal obligations are general obligations supported by the general taxing authority of the issuer, and in some cases are insured.  Obligations issued by school districts are supported by state aid.  For any non-rated municipal securities, credit analysis is performed in-house based upon data that has been submitted by the issuers to the NY State Comptroller. That analysis shows no deterioration in the credit worthiness of the municipalities.  Subsequent to December 31, 2014, there were no securities downgraded below investment grade.
The unrealized losses on these temporarily impaired securities are primarily the result of changes in interest rates for fixed rate securities where the interest rate received is less than the current rate available for new offerings of similar securities, changes in market spreads as a result of shifts in supply and demand, and/or changes in the level of prepayments for mortgage related securities. Because we do not currently intend to sell any of our temporarily impaired securities, and because it is not more likely-than-not we would be required to sell the securities prior to recovery, the impairment is considered temporary.
Schedule of Federal Reserve Bank and Federal Home Loan Bank Stock
Federal Reserve Bank and Federal Home Loan Bank Stock are carried at cost.
	December 31,
	2014			2013
Federal Reserve Bank Stock	$	1,048		$	1,035
Federal Home Loan Bank Stock	3,803			5,246
Total Federal Reserve Bank and Federal Home Loan Bank Stock	$	4,851		$	6,281

Loans

Loans	12 Months Ended
	Dec. 31, 2014
Loans and Leases Receivable Disclosure [Abstract]
Financing Receivables [Text Block]	LOANS (Dollars In Thousands)
	Loan Categories and Past Due Loans
	The following table presents loan balances outstanding as of December 31, 2014 and December 31, 2013 and an analysis of the recorded investment in loans that are past due at these dates.  Generally, Arrow considers a loan past due 30 or more days if the borrower is two or more payments past due.
	Schedule of Past Due Loans by Loan Category
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
	December 31, 2014
	Loans Past Due 30-59 Days	$	124		$	—		$	432		$	30		$	4,137		$	482		$	5,205
	Loans Past Due 60-89 Days	154			—			7			4			1,221			1,495			2,881
	Loans Past Due 90 or More Days	345			—			1,832			3			203			2,999			5,382
	Total Loans Past Due	623			—			2,271			37			5,561			4,976			13,468
	Current Loans	98,888			18,815			319,026			7,628			423,815			531,628			1,399,800
	Total Loans	$	99,511		$	18,815		$	321,297		$	7,665		$	429,376		$	536,604		$	1,413,268
	Loans 90 or More Days Past Due and Still Accruing Interest	$	—		$	—		$	—		$	—		$	—		$	537		$	537
	Nonaccrual Loans	$	473		$	—		$	2,071		$	4		$	411		$	3,940		$	6,899
	December 31, 2013
	Loans Past Due 30-59 Days	$	304		$	—		$	200		$	37		$	3,233		$	529		$	4,303
	Loans Past Due 60-89 Days	601			—			1,200			19			1,041			1,527			4,388
	Loans Past Due 90 or more Days	177			—			2,034			—			98			3,113			5,422
	Total Loans Past Due	1,082			—			3,434			56			4,372			5,169			14,113
	Current Loans	86,811			27,815			284,685			7,593			389,832			455,623			1,252,359
	Total Loans	$	87,893		$	27,815		$	288,119		$	7,649		$	394,204		$	460,792		$	1,266,472
	Loans 90 or More Days Past Due and Still Accruing Interest	$	28		$	—		$	—		$	—		$	—		$	624		$	652
	Nonaccrual Loans	$	352		$	—		$	2,048		$	—		$	219		$	3,860		$	6,479
	The Company disaggregates its loan portfolio into the following six categories:
	Commercial - The Company offers a variety of loan options to meet the specific needs of our commercial customers including term loans, time notes and lines of credit. Such loans are made available to businesses for working capital needs such as inventory and receivables, business expansion and equipment purchases. Generally, a collateral lien is placed on equipment or other assets owned by the borrower. These loans carry a higher risk than commercial real estate loans due to the nature of the underlying collateral, which can be business assets such as equipment and accounts receivable and generally have a lower liquidation value than real estate. In the event of default by the borrower, the Company may be required to liquidate collateral at deeply discounted values. To reduce the risk, management usually obtains personal guarantees of the borrowers.
	Commercial Construction - The Company offers commercial construction and land development loans to finance projects within the communities that we serve. Many projects will ultimately be used by the borrowers’ businesses, while others are developed for resale. These real estate loans are secured by first liens on the real estate, which may include apartments, commercial structures, housing businesses, healthcare facilities, and both owner-occupied and non-owner-occupied facilities. There is enhanced risk during the construction period, since the loan is secured by an incomplete project.
	Commercial Real Estate - The Company offers commercial real estate loans to finance real estate purchases, refinancings, expansions and improvements to commercial properties. Commercial real estate loans are made to finance the purchases of real property which generally consists of real estate with completed structures. These commercial real estate loans are secured by first liens on the real estate, which may include apartments, commercial structures, housing businesses, healthcare facilities, and both owner and non owner-occupied facilities. These loans are typically less risky than commercial loans, since they are secured by real estate and buildings, and are generally originated in amounts of no more than 80% of the appraised value of the property.
	Other Consumer Loans - The Company offers a variety of consumer installment loans to finance personal expenditures. Most of these loans carry a fixed rate of interest with principal repayment terms typically ranging from one to five years, based upon the nature of the collateral and the size of the loan. In addition to installment loans, the Company also offers personal lines of credit and overdraft protection. Several loans are unsecured, which carry a higher risk of loss.
	Automobile - The Company primarily finances the purchases of automobiles indirectly through dealer relationships located throughout upstate New York and Vermont. Most of these loans carry a fixed rate of interest with principal repayment terms typically ranging from three to seven years. The majority of indirect consumer loans are underwritten on a secured basis using the underlying collateral being financed.
	Residential Real Estate Mortgages - Residential real estate loans consist primarily of loans secured by first or second mortgages on primary residences. We originate adjustable-rate and fixed-rate one-to-four-family residential real estate loans for the construction, purchase or refinancing of a mortgage. These loans are collateralized primarily by owner-occupied properties generally located in the Company’s market area. Loans on one-to-four-family residential real estate are generally originated in amounts of no more than 85% of the purchase price or appraised value (whichever is lower), or have private mortgage insurance. The Company’s underwriting analysis for residential mortgage loans typically includes credit verification, independent appraisals, and a review of the borrower’s financial condition. Mortgage title insurance and hazard insurance are normally required. Construction loans have a unique risk, because they are secured by an incomplete dwelling. This risk is reduced through periodic site inspections, including one at each loan draw period. In addition, the Company offers fixed home equity loans as well as home equity lines of credit to consumers to finance home improvements, debt consolidation, education and other uses.  Our policy allows for a maximum loan to value ratio of 80%.  The Company originates home equity lines of credit and second mortgage loans (loans secured by a second junior lien position on one-to-four-family residential real estate).  Risk is generally reduced through underwriting criteria, which include credit verification, appraisals, a review of the borrower's financial condition and personal cash flows.  A security interest, with title insurance when necessary, is taken in the underlying real estate.
	Allowance for Loan Losses
	The following table presents a rollforward of the allowance for loan losses and other information pertaining to the allowance for loan losses:
	Allowance for Loan Losses
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Unallocated			Total
	Rollfoward of the Allowance for Loan Losses for the Year Ended:
	31-Dec-13	$	1,886		$	417		$	3,545		$	272		$	4,206		$	3,026		$	1,082		$	14,434
	Charge-offs	(212		)	—			—			(41		)	(677		)	(91		)				(1,021		)
	Recoveries	86			—			—			6			217			—						309
	Provision	340			(135		)	301			22			1,205			434			(319		)	1,848
	31-Dec-14	$	2,100		$	282		$	3,846		$	259		$	4,951		$	3,369		$	763		$	15,570
	31-Dec-12	$	2,344		$	601		$	3,050		$	304		$	4,536		$	3,405		$	1,058		$	15,298
	Charge-offs	(926		)	—			(11		)	(28		)	(431		)	(15		)	—			(1,411		)
	Recoveries	88			—			—			3			256			—			—			347
	Provision	380			(184		)	506			(7		)	(155		)	(364		)	24			200
	December 31, 2013	$	1,886		$	417		$	3,545		$	272		$	4,206		$	3,026		$	1,082		$	14,434
	31-Dec-11	$	1,927		$	602		$	3,136		$	350		$	4,496		$	3,414		$	1,078		$	15,003
	Charge-offs	(90		)	—			(206		)	(52		)	(401		)	(33		)	—			(782		)
	Recoveries	23			—			—			9			200			—			—			232
	Provision	484			(1		)	120			(3		)	241			24			(20		)	845
	31-Dec-12	$	2,344		$	601		$	3,050		$	304		$	4,536		$	3,405		$	1,058		$	15,298
	Allowance for Loan Losses
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Unallocated			Total
	31-Dec-14
	Allowance for loan losses - Loans Individually Evaluated for Impairment	$	—		$	—		$	—		$	—		$	—		$	109		$	—		$	109
	Allowance for loan losses - Loans Collectively Evaluated for Impairment	$	2,100		$	282		$	3,846		$	259		$	4,951		$	3,260		$	763		$	15,461
	Ending Loan Balance - Individually Evaluated for Impairment	$	494		$	—		$	1,492		$	—		$	118		$	2,237		$	—		$	4,341
	Ending Loan Balance - Collectively Evaluated for Impairment	$	99,017		$	18,815		$	319,805		$	7,665		$	429,258		$	534,367		$	—		$	1,408,927
	December 31, 2013
	Allowance for loan losses - Loans Individually Evaluated for Impairment	$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—
	Allowance for loan losses - Loans Collectively Evaluated for Impairment	$	1,886		$	417		$	3,545		$	272		$	4,206		$	3,026		$	1,082		$	14,434
	Ending Loan Balance - Individually Evaluated for Impairment	$	221		$	—		$	1,785		$	—		$	173		$	2,309		$	—		$	4,488
Ending Loan Balance - Collectively Evaluated for Impairment	$	87,672		$	27,815		$	286,334		$	7,649		$	394,031		$	458,483		$	—		$	1,261,984
Through the provision for loan losses, an allowance for loan losses is maintained that reflects our best estimate of the inherent risk of loss in the Company’s loan portfolio as of the balance sheet date. Additions are made to the allowance for loan losses through a periodic provision for loan losses. Actual loan losses are charged against the allowance for loan losses when loans are deemed uncollectible and recoveries of amounts previously charged off are recorded as credits to the allowance for loan losses.
Our loan officers and risk managers meet at least quarterly to discuss and review the conditions and risks associated with certain criticized and classified commercial-related relationships. In addition, our independent internal loan review department performs periodic reviews of the credit quality indicators on individual loans in our commercial loan portfolio.
We use a two-step process to determine the provision for loan losses and the amount of the allowance for loan losses. We measure impairment on our impaired loans on a quarterly basis. Our impaired loans are generally nonaccrual loans over $250 thousand and all troubled debt restructured loans. Our impaired loans are generally considered to be collateral dependent with the specific reserve, if any, determined based on the value of the collateral less estimated costs to sell.
The remainder of the portfolio is evaluated on a pooled basis, as described below. For each homogeneous loan pool, we estimate a total loss factor based on the historical net loss rates adjusted for applicable qualitative factors. We update the total loss factors assigned to each loan category on a quarterly basis. Our indirect automobile loan portfolio reflects a modest shift, since mid 2013, to a slightly larger percentage of loans within the portfolio comprised of loans to individuals with lower credit scores. For the commercial, commercial construction, and commercial real estate categories, we further segregate the loan categories by credit risk profile (pools of loans graded pass, special mention and accruing substandard). Additional description of the credit risk classifications is detailed in the Credit Quality Indicators section of this note.
We determine the historical net loss rate for each loan category using a trailing three-year net charge-off average. While historical net loss experience provides a reasonable starting point for our analysis, historical net losses, or even recent trends in net losses, do not by themselves form a sufficient basis to determine the appropriate level of the allowance for loan losses. Therefore, we also consider and adjust historical net loss factors for qualitative factors that impact the inherent risk of loss associated with our loan categories within our total loan portfolio. These include:
•	Changes in the volume and severity of past due, nonaccrual and adversely classified loans
•	Changes in the nature and volume of the portfolio and in the terms of loans
•	Changes in the value of the underlying collateral for collateral dependent loans
•	Changes in lending policies and procedures, including changes in underwriting standards and collection, charge-off, and recovery practices not considered elsewhere in estimating credit losses
•	Changes in the quality of the loan review system
•	Changes in the experience, ability, and depth of lending management and other relevant staff
•	Changes in international, national, regional, and local economic and business conditions and developments that affect the collectability of the portfolio
•	The existence and effect of any concentrations of credit, and changes in the level of such concentrations
•	The effect of other external factors such as competition and legal and regulatory requirements on the level of estimated credit losses in the existing portfolio or pool
While not a significant part of the allowance for loan losses methodology, we also maintain an unallocated portion of the total allowance for loan losses related to the overall level of imprecision inherent in the estimation of the appropriate level of allowance for loan losses.
Loan Credit Quality Indicators
The following table presents the credit quality indicators by loan category at December 31, 2014 and December 31, 2013:
Loan Credit Quality Indicators
				Commercial			Commercial			Other
	Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
December 31, 2014
Credit Risk Profile by Creditworthiness Category:
Satisfactory	$	85,949		$	18,815		$	298,932											$	403,696
Special Mention	2,442			—			3,718												6,160
Substandard	11,120			—			18,647												29,767
Doubtful	—			—			—												—
Credit Risk Profile Based on Payment Activity:
Performing										$	7,661		$	428,965		$	532,127		968,753
Nonperforming										4			411			4,477			4,892
December 31, 2013
Credit Risk Profile by Creditworthiness Category:
Satisfactory	$	79,966		$	27,815		$	267,612											$	375,393
Special Mention	204			—			634												838
Substandard	7,723			—			19,873												27,596
Doubtful	—			—			—												—
Credit Risk Profile Based on Payment Activity:
Performing										$	7,649		$	393,985		$	456,308		$	857,942
Nonperforming										—			219			4,484			4,703
For the purposes of the table above, nonperforming automobile, residential and other consumer loans are those loans on nonaccrual status or are 90 days or more past due and still accruing interest.
For the allowance calculation, we use an internally developed system of five credit quality indicators to rate the credit worthiness of each commercial loan defined as follows:
1) Satisfactory - "Satisfactory" borrowers have acceptable financial condition with satisfactory record of earnings and sufficient historical and projected cash flow to service the debt.  Borrowers have satisfactory repayment histories and primary and secondary sources of repayment can be clearly identified;
2) Special Mention - Loans in this category have potential weaknesses that deserve management’s close attention.  If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the asset or in the institution’s credit position at some future date.  "Special mention" assets are not adversely classified and do not expose an institution to sufficient risk to warrant adverse classification.  Loans which might be assigned this credit quality indicator include loans to borrowers with deteriorating financial strength and/or earnings record and loans with potential for problems due to weakening economic or market conditions;
3) Substandard - Loans classified as “substandard” are inadequately protected by the current sound net worth or paying capacity of the borrower or the collateral pledged, if any.  Loans in this category have well defined weaknesses that jeopardize the repayment.  They are characterized by the distinct possibility that the bank will sustain some loss if the deficiencies are not corrected.  “Substandard” loans may include loans which are likely to require liquidation of collateral to effect repayment, and other loans where character or ability to repay has become suspect. Loss potential, while existing in the aggregate amount of substandard assets, does not have to exist in individual assets classified substandard;
4) Doubtful - Loans classified as “doubtful” have all of the weaknesses inherent in those classified as “substandard” with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of current existing facts, conditions, and values highly questionable and improbable.  Although possibility of loss is extremely high, classification of these loans as “loss” has been deferred due to specific pending factors or events which may strengthen the value (i.e. possibility of additional collateral, injection of capital, collateral liquidation, debt restructure, economic recovery, etc).  Loans classified as “doubtful” need to be placed on non-accrual; and
5) Loss - Loans classified as “loss” are considered uncollectible and of such little value that their continuance as bankable assets is not warranted.  As of the date of the balance sheet, all loans in this category have been charged-off to the allowance for loan losses.
Commercial loans are generally evaluated on an annual basis depending on the size and complexity of the loan relationship, unless the credit related quality indicator falls to a level of "special mention" or below, when the loan is evaluated quarterly.  The credit quality indicator is one of the factors used in assessing the level of inherent risk of loss in our commercial related loan portfolios.
Impaired Loans
The following table presents information on impaired loans based on whether the impaired loan has a recorded allowance or no recorded allowance:
Impaired Loans
				Commercial			Commercial			Other
	Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
December 31, 2014
Recorded Investment:
With No Related Allowance	$	494		$	—		$	1,492		$	—		$	118		$	1,678		$	3,782
With a Related Allowance	—			—			—			—			—			559			559
Unpaid Principal Balance:
With No Related Allowance	$	494		$	—		$	1,492		$	—		$	118		$	1,678		$	3,782
With a Related Allowance	—			—			—			—			—			559			559
December 31, 2013
Recorded Investment:
With No Related Allowance	$	221		$	—		$	1,785		$	—		$	173		$	2,309		$	4,488
With a Related Allowance	—			—			—			—			—			—			$	—
Unpaid Principal Balance:
With No Related Allowance	$	221		$	—		$	1,785		$	—		$	173		$	2,309		$	4,488
With a Related Allowance	—			—			—			—			—			—			$	—
For the Year-To-Date Period Ended:
December 31, 2014
Average Recorded Balance:
With No Related Allowance	$	348		$	—		$	1,492		$	—		$	121		$	1,673		$	3,634
With a Related Allowance	—			—			—			—			—			546			$	546
Interest Income Recognized:
With No Related Allowance	$	11		$	—		$	—		$	—		$	7		$	1		$	19
With a Related Allowance	—			—			—			—			—			—			—
Cash Basis Income:
With No Related Allowance	$	—		$	—		$	—		$	—		$	—		$	—		$	—
With a Related Allowance	—			—			—			—			—			—			—
Related Allowance	—			—			—			—			—			109			$	109
December 31, 2013
Average Recorded Balance:
With No Related Allowance	$	133		$	—		$	2,157		$	—		$	188		$	1,700		$	4,178
With a Related Allowance	694			—			—			—			—			—			$	694
Interest Income Recognized:
With No Related Allowance	$	4		$	—		$	—		$	—		$	9		$	8		$	21
With a Related Allowance	—			—			—			—			—			—			$	—
Cash Basis Income:
With No Related Allowance	$	—		$	—		$	—		$	—		$	—		$	—		$	—
With a Related Allowance	—			—			—			—			—			—			$	—
December 31, 2012
Average Recorded Balance:
With No Related Allowance	$	56		$	—		$	2,241		$	—		$	236		$	1,599		$	4,132
With a Related Allowance	$	694		$	—		$	—		$	—		$	—		$	—		$	694
Interest Income Recognized:
With No Related Allowance	$	6		$	—		$	64		$	—		$	12		$	9		$	91
With a Related Allowance	—			—			—			—			—			—			$	—
Cash Basis Income:
With No Related Allowance	$	—		$	—		$	64		$	—		$	—		$	—		$	64
With a Related Allowance	$	—		$	—		$	—		$	—		$	—		$	—		$	—
At December 31, 2014 and December 31, 2013, all impaired loans were considered to be collateral dependent and were therefore evaluated for impairment based on the fair value of collateral less estimated cost to sell. Interest income recognized in the table above, represents income earned after the loans became impaired and includes restructured loans in compliance with their modified terms and nonaccrual loans where we have recognized interest income on a cash basis.
Loans Modified in Trouble Debt Restructurings
The following table presents information on loans modified in trouble debt restructurings during the periods indicated:
Loans Modified in Trouble Debt Restructurings During the Period
				Commercial			Commercial			Other
	Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
For the Year Ended:
December 31, 2014
Number of Loans	—			—			—			—			4			1			5
Pre-Modification Outstanding Recorded Investment	$	—		$	—		$	—		$	—		$	36		$	574		$	610
Post-Modification Outstanding Recorded Investment	$	—		$	—		$	—		$	—		$	36		$	574		$	610
Subsequent Default, Number of Contracts	—			—			—			—			—			—			—
Subsequent Default, Recorded Investment	—			—			—			—			—			—			—
Commitments to lend additional funds to modified loans	—			—			—			—			—			—			—
December 31, 2013
Number of Loans	1			—			—			—			9			—			10
Pre-Modification Outstanding Recorded Investment	$	169		$	—		$	—		$	—		$	88		$	—		$	257
Post-Modification Outstanding Recorded Investment	$	200		$	—		$	—		$	—		$	88		$	—		$	288
Subsequent Default, Number of Contracts	—			—			—			—			—			—			—
Subsequent Default, Recorded Investment	—			—			—			—			—			—			—
Commitments to lend additional funds to modified loans	—			—			—			—			—			—			—
December 31, 2012
Number of Loans	—			—			2			—			17			—			19
Pre-Modification Outstanding Recorded Investment	$	—		$	—		$	47		$	—		$	160		$	—		$	207
Post-Modification Outstanding Recorded Investment	$	—		$	—		$	47		$	—		$	160		$	—		$	207
Subsequent Default, Number of Contracts	—			—			—			—			—			—			—
Subsequent Default, Recorded Investment	—			—			—			—			—			—			—
Commitments to lend additional funds to modified loans	—			—			—			—			—			—			—
In general, loans requiring modification are restructured to accommodate the projected cash-flows of the borrower. Such modifications may involve a reduction of the interest rate, a significant deferral of payments or forgiveness of a portion of the outstanding principal balance. As indicated in the table above, no loans modified during the preceding twelve months subsequently defaulted as of December 31, 2014 or December 31, 2013.
Schedule of Supplemental Loan Information
	2014			2013
Supplemental Information:
Unamortized deferred loan origination costs, net of deferred loan	$	2,771		$	2,152
origination fees, included in the above balances
Overdrawn deposit accounts, included in the above balances	973			501
Pledged loans secured by one-to-four family residential mortgages	313,355			270,372
under a blanket collateral agreement to secure borrowings from
the Federal Home Loan Bank of New York
Residential real estate loans serviced for Freddie Mac, not included	158,598			156,593
in the balances above
Loans held for sale at period-end, included in the above balances	398			64
Loans to Related Parties:
Balance at beginning of year	$	7,769		$	17,447
Adjustment due to change in composition of related parties	—			(8,819		)
New loans and renewals, during the year	694			2,253
Repayments, during the year	(2,460		)	(3,112		)
Balance at end of year	$	6,003		$	7,769

Premises_and_Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	PREMISES AND EQUIPMENT (In Thousands)
	A summary of premises and equipment at December 31, 2014 and 2013 is presented below:
		2014			2013
	Land and Bank Premises	$	35,062		$	35,114
	Equipment, Furniture and Fixtures	22,003			20,851
	Leasehold Improvements	1,218			1,190
	Total Cost	58,283			57,155
	Accumulated Depreciation and Amortization	(29,795		)	(28,001		)
	Net Premises and Equipment	$	28,488		$	29,154
	Amounts charged to expense for depreciation totaled $2,238, $1,928 and $1,521 in 2014, 2013 and 2012, respectively.

Other_Intangible_Assets

Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	OTHER INTANGIBLE ASSETS (In Thousands)
	The following table presents information on Arrow’s other intangible assets (other than goodwill) as of December 31, 2014, 2013 and 2012:
		Depositor			Mortgage			Customer Intangibles1			Total
		Intangibles1			Servicing
					Rights2
	Gross Carrying Amount, December 31, 2014	$	2,247		$	1,715		$	4,451		$	8,413
	Accumulated Amortization	(2,237		)	(883		)	(1,668		)	(4,788		)
	Net Carrying Amount, December 31, 2014	$	10		$	832		$	2,783		$	3,625
	Gross Carrying Amount, December 31, 2013	$	2,247		$	1,582		$	4,451		$	8,280
	Accumulated Amortization	(2,186		)	(622		)	(1,332		)	(4,140		)
	Net Carrying Amount, December 31, 2013	$	61		$	960		$	3,119		$	4,140
	Rollforward of Intangible Assets:
	Balance, December 31, 2011	$	286		$	599		$	3,864		$	4,749
	Intangible Assets Acquired	—			417			—			417
	Amortization of Intangible Assets	(133		)	(157		)	(384		)	(674		)
	Balance, December 31, 2012	153			859			3,480			4,492
	Intangible Assets Acquired	—			331			—			331
	Amortization of Intangible Assets	(92		)	(230		)	(361		)	(683		)
	Balance, December 31, 2013	61			960			3,119			4,140
	Intangible Assets Acquired	—			133			—			133
	Amortization of Intangible Assets	(51		)	(261		)	(336		)	(648		)
	Balance, December 31, 2014	$	10		$	832		$	2,783		$	3,625
	1 Amortization of depositor intangibles and customer intangibles are reported in the consolidated statements of income as a component of other operating expense.
	2 Amortization of mortgage servicing rights is reported in the consolidated statements of income as a reduction of mortgage servicing fee income, which is included with fees for other services to customers.
	The following table presents the remaining estimated annual amortization expense for Arrow's intangible assets as of December 31, 2014:
		Depositor			Mortgage			Customer Intangibles1			Total
		Intangibles1			Servicing
					Rights2
	Estimated Annual Amortization Expense:
	2015	$	10		$	252		$	319		$	581
	2016	—			232			301			533
	2017	—			172			281			453
	2018	—			118			263			381
	2019	—			45			245			290
	Later Years	—			13			1,374			1,387
	Total	$	10		$	832		$	2,783		$	3,625
	1 Amortization of depositor intangibles and customer intangibles are reported in the consolidated statements of income as a component of other operating expense.
	2 Amortization of mortgage servicing rights is reported in the consolidated statements of income as a reduction of mortgage servicing fee income, which is included with fees for other services to customers.

Guarantees

Guarantees	12 Months Ended
	Dec. 31, 2014
Guarantees [Abstract]
Guarantees [Text Block]	GUARANTEES (Dollars In Thousands)
	The following table presents the notional amount and fair value of Arrow's off-balance sheet commitments to extend credit and commitments under standby letters of credit as of December 31, 2014 and 2013:
	Balance at December 31,	2014		2013
	Notional Amount:
	Commitments to Extend Credit	$	249,803	$	237,940
	Standby Letters of Credit	3,317		3,345
	Fair Value:
	Commitments to Extend Credit	$	—	$	—
	Standby Letters of Credit	39		65
	Arrow is party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers.  These financial instruments include commitments to extend credit and standby letters of credit.  Commitments to extend credit include home equity lines of credit, commitments for residential and commercial construction loans and other personal and commercial lines of credit.  Those instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets.  The contract or notional amounts of those instruments reflect the extent of the involvement Arrow has in particular classes of financial instruments.
	Arrow's exposure to credit loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit and standby letters of credit is represented by the contractual notional amount of those instruments.  Arrow uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments.
	Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract.  Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee.  Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements.  Arrow evaluates each customer's creditworthiness on a case-by-case basis.  Home equity lines of credit are secured by residential real estate.  Construction lines of credit are secured by underlying real estate.  For other lines of credit, the amount of collateral obtained, if deemed necessary by Arrow upon extension of credit, is based on management's credit evaluation of the counterparty.  Collateral held varies, but may include accounts receivable, inventory, property, plant and equipment, and income-producing commercial properties.  Most of the commitments are variable rate instruments.
	Arrow does not issue any guarantees that would require liability-recognition or disclosure, other than its standby letters of credit.
	Arrow has issued conditional commitments in the form of standby letters of credit to guarantee payment on behalf of a customer and guarantee the performance of a customer to a third party.  Standby letters of credit generally arise in connection with lending relationships. The credit risk involved in issuing these instruments is essentially the same as that involved in extending loans to customers. Contingent obligations under standby letters of credit at December 31, 2014 and 2013 represent the maximum potential future payments Arrow could be required to make.  Typically, these instruments have terms of 12 months or less and expire unused; therefore, the total amounts do not necessarily represent future cash requirements.  Each customer is evaluated individually for creditworthiness under the same underwriting standards used for commitments to extend credit and on-balance sheet instruments.  Company policies governing loan collateral apply to standby letters of credit at the time of credit extension.  Loan-to-value ratios will generally range from 50% for movable assets, such as inventory, to 100% for liquid assets, such as bank CD's.  Fees for standby letters of credit range from 1% to 3% of the notional amount.  Fees are collected upfront and amortized over the life of the commitment. The carrying amount and fair value of Arrow's standby letters of credit at December 31, 2014 and 2013 were insignificant.  The fair value of standby letters of credit is based on the fees currently charged for similar agreements or the cost to terminate the arrangement with the counterparties.
	The fair value of commitments to extend credit is determined by estimating the fees to enter into similar agreements, taking into account the remaining terms and present creditworthiness of the counterparties, and for fixed rate loan commitments, the difference between the current and committed interest rates.  Arrow provides several types of commercial lines of credit and standby letters of credit to its commercial customers.  The pricing of these services is not isolated as Arrow considers the customer's complete deposit and borrowing relationship in pricing individual products and services.  The commitments to extend credit also include commitments under home equity lines of credit, for which Arrow charges no fee.  The carrying value and fair value of commitments to extend credit are not material and Arrow does not expect to incur any material loss as a result of these commitments.
	In the normal course of business, Arrow and its subsidiary banks become involved in a variety of routine legal proceedings.  At present, there are no legal proceedings pending or threatened, which in the opinion of management and counsel, would result in a material loss to Arrow.

Time_Deposits

Time Deposits	12 Months Ended
	Dec. 31, 2014
Time Deposits [Abstract]
Deposit Liabilities Disclosures [Text Block]	TIME DEPOSITS (Dollars In Thousands)
	The following summarizes the contractual maturities of time deposits during years subsequent to December 31, 2014:
	Year of Maturity	Total Time
		Deposits
	2015	$	124,406
	2016	28,487
	2017	19,869
	2018	11,845
	2019	17,126
	2020 and Beyond	4,110
	Total	$	205,843

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt [Text Block]	DEBT (Dollars in Thousands)
	Schedule of Short-Term Borrowings:
		2014			2013
	Balances at December 31:
	Overnight Advances from the Federal Home Loan Bank of New York	$	41,000		$	53,000
	Securities Sold Under Agreements to Repurchase	19,421			11,777
	Total Short-Term Borrowings	$	60,421		$	64,777
	Maximum Borrowing Capacity at December 31:
	Federal Funds Purchased	$	35,000		$	30,000
	Overnight Advances from the Federal Home Loan Bank of New York	203,885			214,000
	Federal Reserve Bank of New York	307,159			302,000
	Securities sold under agreements to repurchase mature in one day.  Arrow maintains effective control over the securities underlying the agreements.
	Arrow's subsidiary banks have in place unsecured federal funds lines of credit with three correspondent banks. As a member of the FHLBNY, we participate in the advance program which allows for overnight and term advances up to the limit of pledged collateral, including FHLBNY stock, mortgage-backed securities and residential real estate loans (see Note 4. "Investment Securities" and Note 5. "Loans").  Our investment in FHLBNY stock is proportional to the total of our overnight and term advances (see the Schedule of Federal Reserve Bank and Federal Home Loan Bank Stock in Note 4. "Investment Securities"). Our bank subsidiaries have also established borrowing facilities with the Federal Reserve Bank of New York for potential “discount window” advances, pledging certain consumer loans as collateral (see Note 5. "Loans").
	Long Term Debt - FHLBNY Term Advances
	In addition to overnight advances, Arrow also borrows longer-term funds from the FHLBNY.  Certain borrowings are in the form of “convertible advances.”  These advances have a set final maturity, but are callable by the FHLBNY at certain dates beginning no earlier than one year from the issuance date.  If the advances are called, Arrow may elect to have the funds replaced by the FHLBNY at the then prevailing market rate of interest.
	Maturity Schedule of FHBLNY Term Advances:
			Balances					Weighted Average Rate
	Final Maturity		2014			2013		2014		2013
	First Year		$	10,000		$	10,000	3.88	%	1.43	%
	Second Year		—			10,000		—	%	3.88	%
	Third Year		—			—		—	%	—	%
	Total		$	10,000		$	20,000	3.88	%	2.66	%
	Long Term Debt - Guaranteed Preferred Beneficial Interests in Corporation's Junior Subordinated Debentures
	During 2014, there were outstanding two classes of financial instruments issued by two separate subsidiary business trusts of Arrow, identified as “Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts” on the Consolidated Balance Sheets and the Consolidated Statements of Income.
	The first of the two classes of trust-issued instruments outstanding at year-end was issued by Arrow Capital Statutory Trust II ("ACST II"), a Delaware business trust established on July 16, 2003, upon the filing of a certificate of trust with the Delaware Secretary of State.  In July 2003, ACST II issued all of its voting (common) stock to Arrow and issued and sold to an unaffiliated purchaser 30-year guaranteed preferred beneficial interests in the trust's assets ("ACST II trust preferred securities"). The rate on the securities is variable, adjusting quarterly to the 3-month LIBOR plus 3.15%.  ACST II used the proceeds of the sale of its trust preferred securities to purchase an identical amount of junior subordinated debentures issued by Arrow that bear an interest rate identical at all times to the rate payable on the ACST II trust preferred securities.  The ACST II trust preferred securities became redeemable after July 23, 2008 and mature on July 23, 2033.
	The second of the two classes of trust-issued instruments outstanding at year-end was issued by Arrow Capital Statutory Trust III ("ACST III"), a Delaware business trust established on December 23, 2004, upon the filing of a certificate of trust with the Delaware Secretary of State. On December 28, 2004, the ACST III issued all of its voting (common) stock to Arrow and issued and sold to an unaffiliated purchaser 30-year guaranteed preferred beneficial interests in the trust's assets ("ACST III").  The rate on the ACST III trust preferred securities is a variable rate, adjusted quarterly, equal to the 3-month LIBOR plus 2.00%.  ACST III used the proceeds of the sale of its trust preferred securities to purchase an identical amount of junior subordinated debentures issued by Arrow that bear an interest rate identical at all times to the rate payable on the ACST III trust preferred securities.  The ACST III trust preferred securities became redeemable on or after March 31, 2010 and mature on December 28, 2034.
	The primary assets of the two subsidiary trusts having trust preferred securities outstanding at year-end, ACST II and ACST III (the “Trusts”), are Arrow's junior subordinated debentures discussed above, and the sole revenues of the Trusts are payments received by them from Arrow with respect to the junior subordinated debentures.  The trust preferred securities issued by the Trusts are non-voting.  All common voting securities of the Trusts are owned by Arrow.  Arrow used the net proceeds from its sale of junior subordinated debentures to the Trusts, facilitated by the Trust’s sale of their trust preferred securities to the purchasers thereof, for general corporate purposes.  The trust preferred securities and underlying junior subordinated debentures, with associated expense that is tax deductible, qualify as Tier I capital under regulatory definitions.
	Arrow's primary source of funds to pay interest on the debentures that are held by the Trusts are current dividends received by Arrow from its subsidiary banks.  Accordingly, Arrow's ability to make payments on the debentures, and the ability of the Trusts to make payments on their trust preferred securities, are dependent upon the continuing ability of Arrow's subsidiary banks to pay dividends to Arrow.  Since the trust preferred securities issued by the subsidiary trusts and the underlying junior subordinated debentures issued by Arrow at December 31, 2014, 2013 and 2012 are classified as debt for financial statement purposes, the expense associated with these securities is recorded as interest expense in the consolidated statements of income for the three years.
	Schedule of Guaranteed Preferred Beneficial Interests in Corporation's Junior Subordinated Debentures
		2014			2013
	ACST II
	Balance at December 31,	$	10,000		$	10,000
	Period-End Interest Rate	3.38		%	3.4		%
	ACST III
	Balance at December 31,	$	10,000		$	10,000
	Period-End Interest Rate	2.23		%	2.25		%

Comprehensive_Income

Comprehensive Income	12 Months Ended
	Dec. 31, 2014
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income, Noncontrolling Interest [Text Block]	COMPREHENSIVE INCOME (Dollars In Thousands)
	The following table presents the components of other comprehensive income for the years ended December 31, 2014, 2013 and 2012:
	Schedule of Comprehensive Income
		Before-Tax				Tax			Net-of-Tax
		Amount				(Expense)			Amount
						Benefit
	2014
	Net Unrealized Securities Holding Gains Arising During the Period	$	356			$	(124	)	$	232
	Reclassification Adjustment for Securities Gains Included in Net Income	(110		)		43			(67		)
	Net Retirement Plan Loss	(4,610		)		1,764			(2,846		)
	Net Retirement Plan Prior Service Credit	(570		)		223			(347		)
	Amortization of Net Retirement Plan Actuarial Loss	474				(186		)	288
	Accretion of Net Retirement Plan Prior Service Credit	(87		)		34			(53		)
	Other Comprehensive Income	$	(4,547	)		$	1,754		$	(2,793	)
	2013
	Net Unrealized Securities Holding Gains Arising During the Period	$	(4,843	)		$	1,918		$	(2,925	)
	Reclassification Adjustment for Securities Gains Included in Net Income	(540		)		214			(326		)
	Net Retirement Plan Gain	10,640				(4,215		)	6,425
	Amortization of Net Retirement Plan Actuarial Loss	1,513				(599		)	914
	Accretion of Net Retirement Plan Prior Service Credit	2				(1		)	1
	Other Comprehensive Income	$	6,772			$	(2,683	)	$	4,089
	2012
	Net Unrealized Securities Holding Gains Arising During the Period	$	(1,094	)		$	433		$	(661	)
	Reclassification Adjustment for Securities Gains Included in Net Income	(865		)		343			(522		)
	Net Retirement Plan Loss	(2,218		)		878			(1,340		)
	Net Retirement Plan Prior Service Credit	(405		)		160			(245		)
	Amortization of Net Retirement Plan Actuarial Loss	1,677				(664		)	1,013
	Accretion of Net Retirement Plan Prior Service Credit	(20		)		8			(12		)
	Other Comprehensive Income	$	(2,925	)		$	1,158		$	(1,767	)
	The following table presents the changes in accumulated other comprehensive income by component:
	Changes in Accumulated Other Comprehensive Income (Loss) by Component (1)
		Unrealized				Defined Benefit Plan Items
		Gains and
		Losses on							Net Prior
		Available-for-				Net Gain			Service
		Sale Securities				(Loss)			(Cost ) Credit			Total
	For the Year-To-Date periods ended:
	31-Dec-13	$	2,374			$	(6,697	)	$	(50	)	$	(4,373	)
	Other comprehensive income (loss) before reclassifications	232				(2,846		)	(347		)	(2,961		)
	Amounts reclassified from accumulated other comprehensive income (loss)	(67		)		288			(53		)	168
	Net current-period other comprehensive income	165				(2,558		)	(400		)	(2,793		)
	December 31, 2014	$	2,539			$	(9,255	)	$	(450	)	$	(7,166	)
	December 31, 2012	$	5,625			$	(14,036	)	$	(51	)	$	(8,462	)
	Other comprehensive income (loss) before reclassifications	(2,925		)		6,425			—			3,500
	Amounts reclassified from accumulated other comprehensive income (loss)	(326		)		914			1			589
	Net current-period other comprehensive income	(3,251		)		7,339			1			4,089
	December 31, 2013	$	2,374			$	(6,697	)	$	(50	)	$	(4,373	)
	December 31, 2011	$	6,808			$	(13,709	)	$	206		$	(6,695	)
	Other comprehensive income (loss) before reclassifications	(661		)		(1,340		)	(245		)	(2,246		)
	Amounts reclassified from accumulated other comprehensive income (loss)	(522		)		1,013			(12		)	479
	Net current-period other comprehensive income	(1,183		)		(327		)	(257		)	(1,767		)
	December 31, 2012	$	5,625			$	(14,036	)	$	(51	)	$	(8,462	)
	(1) All amounts are net of tax. Amounts in parentheses indicate debits.
	The following table presents the reclassifications out of accumulated other comprehensive income:
	Reclassifications Out of Accumulated Other Comprehensive Income (1)
			Amounts Reclassified
	Details about Accumulated Other		from Accumulated Other				Affected Line Item in the Statement
	Comprehensive Income Components		Comprehensive Income				Where Net Income Is Presented
	For the Year-to-date periods ended:
	December 31, 2014
	Unrealized gains and losses on available-for-sale securities
			$	110			Gain on Securities Transactions, Net
			110				Total before tax
			(43		)		Provision for Income Taxes
		$	67			Net of tax
Amortization of defined benefit pension items
Prior-service costs		$	87		(2)	Salaries and Employee Benefits
Actuarial gains/(losses)		(474		)	(2)	Salaries and Employee Benefits
		(387		)		Total before tax
		152				Provision for Income Taxes
		$	(235	)		Net of tax
Total reclassifications for the period		$	(168	)		Net of tax
December 31, 2013
Unrealized gains and losses on available-for-sale securities
		$	540			Gain on Securities Transactions, Net
		540				Total before tax
		(214		)		Provision for Income Taxes
		$	326			Net of tax
Amortization of defined benefit pension items
Prior-service costs		(2		)	(2)	Salaries and Employee Benefits
Actuarial gains/(losses)		$	(1,513	)	(2)	Salaries and Employee Benefits
		(1,515		)		Total before tax
		600				Provision for Income Taxes
		$	(915	)		Net of tax
Total reclassifications for the period		$	(589	)		Net of tax
Reclassifications Out of Accumulated Other Comprehensive Income (1)
		Amounts Reclassified
Details about Accumulated Other		from Accumulated Other				Affected Line Item in the Statement
Comprehensive Income Components		Comprehensive Income				Where Net Income Is Presented
December 31, 2012
Unrealized gains and losses on available-for-sale securities
		$	865			Gain on Securities Transactions, Net
		865				Total before tax
		(343		)		Provision for Income Taxes
		$	522			Net of tax
Amortization of defined benefit pension items
Prior-service costs		20			(2)	Salaries and Employee Benefits
Actuarial gains/(losses)		$	(1,677	)	(2)	Salaries and Employee Benefits
		(1,657		)		Total before tax
		656				Provision for Income Taxes
		$	(1,001	)		Net of tax
Total reclassifications for the period		$	(479	)		Net of tax
(1) Amounts in parentheses indicate debits to profit/loss.
(2) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see pension footnote for additional details).

Stock_Based_Compensation

Stock Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	STOCK BASED COMPENSATION (Dollars In Thousands, Except Share and Per Share Amounts)
	Arrow has established two stock based compensation plans: an Incentive and Non-qualified Stock Option Plan (Stock Option Plan) and an Employee Stock Ownership Plan (ESOP).  All share and per share data have been adjusted for the September 2014 2% stock dividend.
	Stock Option Plan
	Options may be granted at a price no less than the greater of the par value or fair market value of such shares on the date on which such option is granted, and generally expire ten years from the date of grant.  The options usually vest over a four-year period.
	Roll Forward Schedule of Stock Option Plan by Shares and Weighted Average Exercise Prices
		Stock Option Plans
	Roll Forward of Shares Outstanding:
	Outstanding at January 1, 2014	397,177
	Granted	75,518
	Exercised	(62,269		)
	Forfeited	(8,984		)
	Outstanding at December 31, 2014	401,442
	Exercisable at December 31, 2014	266,654
	Vested and Expected to Vest	134,788
	Roll Forward of Shares Outstanding - Weighted Average Exercise Price:
	Outstanding at January 1, 2014	$	22.44
	Granted	24.51
	Exercised	23.35
	Forfeited	23.89
	Outstanding at December 31, 2014	22.66
	Exercisable at December 31, 2014	21.74
	Vested and Expected to Vest	24.47
	Weighted Average Remaining Contractual Life (in years):
	Outstanding at December 31, 2014	5.83
	Exercisable at December 31, 2014	4.67
	Vested and Expected to Vest	8.13
	Aggregate Intrinsic Value:
	Outstanding at December 31, 2014	$	1,939
	Exercisable at December 31, 2014	1,533
	Vested and Expected to Vest	406
	Shares Available for Grant at Period-End	445,000
	Schedule of Shares Authorized Under the Stock Option Plan by Exercise Price Range
		Exercise Price Ranges
		$18.71 to $19.48			$20.82			$21.83		$23.30 to $23.95			$24.51 to $25.27		Total
	Outstanding Options at
	31-Dec-14
	Number of Shares Outstanding	72,516			27,470			64,829		153,236			83,391		401,442
	Weighted-Average Remaining Contractual Life (in years)	3.69			1.92			5.08		6.66			8.05		5.83
	Weighted-Average Exercise Price	$	19.24		$	20.82		$	21.83	$	23.61		$	24.6	$	22.55
	Exercisable Options at
	31-Dec-14
	Number of Shares Outstanding	72,516			27,470			64,829		92,333			9,506		266,654
	Weighted-Average Remaining Contractual Life (in years)	3.69			1.92			5.08		6.44			8.05		4.67
	Weighted-Average Exercise Price	$	19.24		$	20.82		$	21.83	$	23.56		$	25.27	$	21.74
	Schedule of Other Stock Option Plan Information
			2014				2013			2012
	Shares Granted		75,518				10,404			78,848
	Weighted Average Grant Date Information:
	Fair Value of Options Granted		$	5.92			$	5.35		$	5.77
	Fair Value Assumptions:
	Dividend Yield		3.97		%		4.2		%	3.93		%
	Expected Volatility		35.3		%		36.57		%	37.43		%
	Risk Free Interest Rate		2.19		%		1.31		%	1.22		%
	Expected Lives (in years)		6.85				6.71			6.46
	Amount Expensed During the Year		$	360			$	372		$	424
	Compensation Costs for Non-vested Awards Not Yet Recognized		478				420			737
	Weighted Average Expected Vesting Period, In Years		1.68				1.45			1.71
	Proceeds From Stock Options Exercised		$	1,454			$	1,254		$	2,105
	Tax Benefits Related to Stock Options Exercised		25				23			68
	Intrinsic Value of Stock Options Exercised		170				267			2,434
	Employee Stock Ownership Plan
	Arrow maintains an employee stock ownership plan (“ESOP”).  Substantially all employees of Arrow and its subsidiaries are eligible to participate upon satisfaction of applicable service requirements.  The ESOP borrowed funds from one of Arrow’s subsidiary banks to purchase outstanding shares of Arrow’s common stock.  The notes require annual payments of principal and interest through 2018.  As the debt is repaid, shares are released from collateral based on the proportion of debt paid to total debt outstanding for the year and allocated to active employees.  In addition, the Company makes additional cash contributions to the Plan each year.
	Schedule of ESOP Compensation Expense
			2014				2013			2012
ESOP Compensation Expense		$	800			$	600		$	550
As the debt is repaid, shares are released from collateral based on the proportion of debt paid to total debt outstanding for the year and allocated to active employees.
Shares pledged as collateral are reported as unallocated ESOP shares in stockholders’ equity.  As shares are released from collateral, Arrow reports compensation expense equal to the current average market price of the shares, and the shares become outstanding for earnings per share computations.  The ESOP shares as of December 31, 2014 were as follows:
Schedule of Shares in ESOP Plan
ESOP Plan Shares:	2014
Allocated Shares	690,853
Shares Released for Allocation During 2013	17,300
Unallocated Shares	71,748
Total ESOP Shares	779,901
Market Value of Unallocated Shares	$	1,972

Retirement_Benefit_Plans

Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]
	:	RETIREMENT BENEFIT PLANS (Dollars in Thousands)
	Arrow sponsors qualified and nonqualified defined benefit pension plans and other postretirement benefit plans for its employees. Arrow maintains a non-contributory pension plan, which covers substantially all employees.  Effective December 1, 2002, all active participants in the qualified defined benefit pension plan were given a one-time irrevocable election to continue participating in the traditional plan design, for which benefits were based on years of service and the participant’s final compensation (as defined), or to begin participating in the new cash balance plan design.  All employees who participate in the plan after December 1, 2002 automatically participate in the cash balance plan design.  The interest credits under the cash balance plan are based on the 30-year U.S. Treasury rate in effect for November of the prior year.  The service credits under the cash balance plan are equal to 6.0% of eligible salaries for employees who become participants on or after January 1, 2003.  For employees in the plan prior to January 1, 2003, the service credits are scaled based on the age of the participant, and range from 6.0% to 12.0%.  The funding policy is to contribute up to the maximum amount that can be deducted for federal income tax purposes and to make all payments required under ERISA.  Arrow also maintains a supplemental non-qualified unfunded retirement plan to provide eligible employees of Arrow and its subsidiaries with benefits in excess of qualified plan limits imposed by federal tax law.
	Arrow has multiple non-pension postretirement benefit plans.  The health care, dental and life insurance plans are contributory, with participants’ contributions adjusted annually.  Arrow’s policy is to fund the cost of postretirement benefits based on the current cost of the underlying policies.  However, the health care plan provision for automatic increases of Company contributions each year is based on the increase in inflation and is limited to a maximum of 5%.
	As of December 31, 2014, Arrow updated its mortality assumption to the RP-2014 Mortality Table for annuitants and non-annuitants with projected generational mortality improvements using Scale MP-2014. The revised assumption resulted in an increase in postretirement liabilities.
	The following tables set forth changes in the plans’ benefit obligations (projected benefit obligation for pension benefits and accumulated benefit obligation for postretirement benefits) and changes in the plans’ assets and the funded status of the pension plans and other postretirement benefit plan at December 31:
	Schedule of Defined Benefit Plan Disclosures
		Employees'			Select			Postretirement
		Pension			Executive			Benefit
		Plan			Retirement			Plans
					Plan
	Defined Benefit Plan Funded Status
	31-Dec-14
	Fair Value of Plan Assets	$	45,704		$	—		$	—
	Benefit Obligation	36,966			5,072			9,170
	Funded Status of Plan	$	8,738		$	(5,072	)	$	(9,170	)
	31-Dec-13
	Fair Value of Plan Assets	$	44,653		$	—		$	—
	Benefit Obligation	33,259			4,459			7,619
	Funded Status of Plan	$	11,394		$	(4,459	)	$	(7,619	)
	Change in Benefit Obligation
	Benefit Obligation, at January 1, 2014	$	33,259		$	4,459		$	7,619
	Service Cost	1,410			10			173
	Interest Cost	1,621			206			374
	Plan Participants' Contributions	—			—			383
	Amendments	—			—			570
	Actuarial Gain	2,909			870			884
	Benefits Paid	(2,233		)	(473		)	(833		)
	Benefit Obligation, at December 31, 2014	$	36,966		$	5,072		$	9,170
	Schedule of Defined Benefit Plan Disclosures
		Employees'			Select			Postretirement
		Pension			Executive			Benefit
		Plan			Retirement			Plans
					Plan
	Benefit Obligation, at January 1, 2013	$	37,046		$	5,324		$	9,213
	Service Cost	1,506			—			211
	Interest Cost	1,261			163			308
	Plan Participants' Contributions	—			—			368
	Amendments	—			—			—
	Actuarial Loss	(3,820		)	(555		)	(1,648		)
	Benefits Paid	(2,734		)	(473		)	(833		)
	Benefit Obligation, at December 31, 2013	$	33,259		$	4,459		$	7,619
	Change in Fair Value of Plan Assets
	Fair Value of Plan Assets, at January 1, 2014	$	44,653		$	—		$	—
	Actual Return on Plan Assets	3,284			—			—
	Employer Contributions	—			473			450
	Plan Participants' Contributions	—			—			383
	Benefits Paid	(2,233		)	(473		)	(833		)
	Fair Value of Plan Assets, at December 31, 2014	$	45,704		$	—		$	—
	Change in Fair Value of Plan Assets, continued
	Fair Value of Plan Assets, at January 1, 2013	$	39,880		$	—		$	—
	Actual Return on Plan Assets	7,507			—			—
	Employer Contributions	—			473			465
	Plan Participants' Contributions	—			—			368
	Benefits Paid	(2,734		)	(473		)	(833		)
	Fair Value of Plan Assets, at December 31, 2013	$	44,653		$	—		$	—
	Accumulated Benefit Obligation at December 31, 2014	$	36,530		$	5,072		$	9,170
	Amounts Recognized in the Consolidated Balance Sheets
	31-Dec-14
	Prepaid Pension Asset	$	8,738		$	—		—
	Accrued Benefit Liability	—			(5,072		)	(9,170		)
	Net Benefit Recognized	$	8,738		$	(5,072	)	$	(9,170	)
	31-Dec-13
	Prepaid Pension Asset	$	11,394		$	—		—
Accrued Benefit Liability	—			(4,459		)	(7,619		)
Net Benefit Recognized	$	11,394		$	(4,459	)	$	(7,619	)
Amounts Recognized in Other Comprehensive Income (Loss)
For the Year Ended December 31, 2014
Net Unamortized Gain Arising During the Period	$	2,855		$	871		$	884
Net Prior Service Cost Arising During the Period	—			—			570
Amortization of Net Loss	(356		)	(93		)	(25		)
Amortization of Prior Service (Cost) Credit	45			(72		)	114
Total Other Comprehensive (Loss) Income for Pension and	$	2,544		$	706		$	1,543
Other Postretirement Benefit Plans
For the Year Ended December 31, 2013
Net Unamortized Loss Arising During the Period	$	(8,438	)	$	(554	)	$	(1,648	)
Net Prior Service Cost Arising During the Period	—			—			—
Amortization of Net Loss	(1,231		)	(140		)	(142		)
Amortization of Prior Service (Cost) Credit	(37		)	(79		)	114
Total Other Comprehensive (Loss) Income for Pension and	$	(9,706	)	$	(773	)	$	(1,676	)
Other Postretirement Benefit Plans
Schedule of Defined Benefit Plan Disclosures
	Employees'			Select			Postretirement
	Pension			Executive			Benefit
	Plan			Retirement			Plans
				Plan
For the Year Ended December 31, 2012
Net Unamortized Loss Arising During the Period	$	1,286		$	441		$	491
Net Prior Service Cost Arising During the Period	—			405			—
Amortization of Net Loss	(1,387		)	(156		)	(134		)
Amortization of Prior Service (Cost) Credit	(41		)	(53		)	114
Total Other Comprehensive (Loss) Income for Pension and	$	(142	)	$	637		$	471
Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income
31-Dec-14
Net Actuarial Loss	$	10,856		$	2,452		$	1,919
Prior Service (Credit) Cost	(210		)	570			379
Total Accumulated Other Comprehensive Income, Before Tax	$	10,646		$	3,022		$	2,298
31-Dec-13
Net Actuarial Loss	$	8,357		$	1,674		$	1,060
Prior Service (Credit) Cost	(255		)	642			(305		)
Total Accumulated Other Comprehensive Income, Before Tax	$	8,102		$	2,316		$	755
Amounts that will be Amortized from Accumulated
Other Comprehensive Income the Next Year
Net Actuarial Loss	$	556		$	121		$	95
Prior Service (Credit) Cost	$	(83	)	$	58		$	(31	)
Net Periodic Benefit Cost
For the Year Ended December 31, 2014
Service Cost	$	1,410		$	10		$	173
Interest Cost	1,621			206			374
Expected Return on Plan Assets	(3,230		)	—			—
Amortization of Prior Service (Credit) Cost	(45		)	72			(114		)
Amortization of Net Loss	356			93			25
Net Periodic Benefit Cost	$	112		$	381		$	458
For the Year Ended December 31, 2013
Service Cost	$	1,506		$	—		$	211
Interest Cost	1,261			163			308
Expected Return on Plan Assets	(2,889		)	—			—
Amortization of Prior Service (Credit) Cost	37			79			(114		)
Amortization of Net Loss	1,232			139			142
Net Periodic Benefit Cost	$	1,147		$	381		$	547
For the Year Ended December 31, 2012
Service Cost	$	1,467		$	87		$	202
Interest Cost	1,436			190			338
Expected Return on Plan Assets	(2,865		)	—			—
Amortization of Prior Service (Credit) Cost	41			53			(114		)
Amortization of Net Loss	1,387			156			134
Net Periodic Benefit Cost	$	1,466		$	486		$	560
Weighted-Average Assumptions Used in
Calculating Benefit Obligation
31-Dec-14
Discount Rate	4.31		%	4.26		%	4.31		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Schedule of Defined Benefit Plan Disclosures
	Employees'			Select			Postretirement
	Pension			Executive			Benefit
	Plan			Retirement			Plans
				Plan
Interest Rate Credit for Determining	3.04		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	4.75		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	4.75		%	4.75		%
Equivalent Lump Sum Amounts
31-Dec-13
Discount Rate	5.1		%	4.85		%	5.1		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	4		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	5.25		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	5.25		%	5.25		%
Equivalent Lump Sum Amounts
Weighted-Average Assumptions Used in
Calculating Net Periodic Benefit Cost
31-Dec-14
Discount Rate	5.1		%	4.85		%	5.1		%
Expected Long-Term Return on Plan Assets	7.5		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	4		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	5.25		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	5.25		%	5.25		%
Equivalent Lump Sum Amounts
31-Dec-13
Discount Rate	3.55		%	3.15		%	3.55		%
Expected Long-Term Return on Plan Assets	7.5		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	3		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	4.5		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	4.5		%	4.5		%
Equivalent Lump Sum Amounts
31-Dec-12
Discount Rate	4.05		%	4.05		%	4.05		%
Expected Long-Term Return on Plan Assets	7.5		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	3.25		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	5		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	5		%	5		%
Equivalent Lump Sum Amounts
Schedule of Defined Benefit Plan Disclosures
Information about Defined Benefit Plan Assets - Employees' Pension Plan
Fair Value Measurements Using:
Asset Category	Quoted Prices			Significant Other Observable Inputs			Significant Unobservable Inputs			Total		Percent of Total		Target Allocation Minimum		Target Allocation Maximum
	in Active Markets			(Level 2)			(Level 3)
	for Identical Assets
	(Level 1)
December 31, 2014
Cash	$	20		$	—		$	—		$	20	—	%	—	%	15	%
Interest-Bearing Money Market Fund	4,322			—			—			4,322		9.5	%	—	%	15	%
Arrow Common Stock1	4,551			—			—			4,551		10	%	—	%	10	%
North Country Funds - Equity 2	18,975			—			—			18,975		41.4	%
Other Mutual Funds - Equity	10,954			—			—			10,954		24	%
Total Equity Funds	29,929			—			—			29,929		65.4	%	66	%	85	%
North Country Funds - Fixed income 2	5,436			—			—			5,436		11.9	%
Other Mutual Funds - Fixed Income	1,446			—			—			1,446		3.2	%
Total Fixed Income Funds	6,882			—			—			6,882		15.1	%	15	%	30	%
Total	$	45,704		$	—		$	—		$	45,704	100	%
December 31, 2013
Cash	$	7		$	—		$	—		$	7	—	%	—	%	15	%
Interest-Bearing Money Market Fund	3,941			—			—			3,941		8.8	%	—	%	15	%
Arrow Common Stock1	4,291			—			—			4,291		9.6	%	—	%	10	%
North Country Funds - Equity 2	17,419			—			—			17,419		39.1	%
Other Mutual Funds - Equity	14,338			—			—			14,338		32.1	%
Total Equity Funds	31,757			—			—			31,757		71.2	%	55	%	85	%
North Country Funds - Fixed income 2	4,309			—			—			4,309		9.6	%
Other Mutual Funds - Fixed Income	348			—			—			348		0.8	%
Total Fixed Income Funds	4,657			—			—			4,657		10.4	%	10	%	30	%
Total	$	44,653		$	—		$	—		$	44,653	100	%
1 Acquisition of Arrow Financial Corporation common stock was under 10% of the total fair value of the employee's pension plan assets at the time of acquisition.
2 The North Country Funds - Equity and the North Country Funds - Fixed Income are publicly traded mutual funds advised by Arrow's subsidiary, North Country Investment Advisers, Inc.
Schedule of Defined Benefit Plan Disclosures
	Employees'			Select			Postretirement
	Pension			Executive			Benefit
	Plan			Retirement			Plans
				Plan
Expected Future Benefit Payments
2015	$	2,163		$	438		$	536
2016	2,334			429			554
2017	2,356			419			565
2018	2,253			409			584
2019	2,256			399			615
2020 - 2024	12,799			1,826			3,323
Estimated Contributions During 2015	$	—		$	438		$	536
Assumed Health Care Cost Trend Rates
31-Dec-14
Health Care Cost Trend							8		%
Rate Assumed for Next Year
Rate to which the Cost Trend							3.89		%
Rate is Assumed to Decline
(the Ultimate Trend Rate)
Year that the Rate Reaches							2075
the Ultimate Trend Rate
31-Dec-13
Health Care Cost Trend							8.5		%
Rate Assumed for Next Year
Rate to which the Cost Trend							5		%
Rate is Assumed to Decline
(the Ultimate Trend Rate)
Year that the Rate Reaches							2021
the Ultimate Trend Rate
Effect of a One-Percentage Point Change in Assumed
Health Care Cost Trend Rates
Effect of a One Percentage Point Increase on							$	60
Service and Interest Cost Components
Effect of a One Percentage Point Decrease on							(49		)
Service and Interest Cost Components
Effect of a One Percentage Point Increase on							782
Accumulated Postretirement Benefit Obligation
Effect of a One Percentage Point Decrease on							(664		)
Accumulated Postretirement Benefit Obligation
Fair Value of Plan Assets (Defined Benefit Plan):
For information on fair value measurements, including descriptions of level 1, 2 and 3 of the fair value hierarchy and the valuation methods employed by Arrow, see Note 2 - “Summary of Significant Accounting Policies” and Note 17 - “Fair Values.”
The fair value of level 1 financial instruments in the table above are based on unadjusted, quoted market prices from exchanges in active markets.
In accordance with ERISA guidelines, the Board authorized the purchase of Arrow common stock up to 10% of the fair market value of the plan's assets at the time of acquisition.
Pension Plan Investment Policies and Strategies:
The Company maintains a non-contributory pension benefit plan covering substantially all employees for the purpose of rewarding long and loyal service to the Company.  The pension assets are held in trust and are invested in a prudent manner for the exclusive purpose of providing benefits to participants.  The investment objective is to achieve an inflation-protected rate of return that meets the actuarial assumption which is used for funding purposes.  The investment strategy attempts to maximize the investment return on assets at a level of risk deemed appropriate by the Company while complying with ERISA and any applicable regulations and laws.  The investment strategy utilizes asset allocation as a principal determinant for establishing the risk/reward profile of the assets. Asset allocation ranges are established, periodically reviewed, and adjusted as funding levels, and participant benefit characteristics change. Active and passive investment management is employed to help enhance the risk/return profile of the assets.
The Plan’s assets are invested in a diversified portfolio of equity securities comprised of companies with small, mid, and large capitalizations.  Both domestic and international equities are allowed to provide further diversification and opportunity for return in potentially higher growth economies with lower correlation of returns.  Growth and value styles of investment are employed to increase the diversification and offer varying opportunities for appreciation.  The fixed income portion of the plan may be invested in U.S. dollar denominated debt securities that shall be rated within the top four ratings categories by nationally recognized ratings agencies.   The fixed income portion will be invested without regard to industry or sector based on analysis of each target security’s structural and repayment features, current pricing and trading opportunities as well as credit quality of the issuer.  Individual bonds with ratings that fall below the Plan’s rating requirements will be sold only when it is in the best interests of the Plan.  Hybrid investments, such as convertible bonds, may be used to provide growth characteristics while offering some protection to declining equity markets by having a fixed income component.  Alternative investments such as Treasury Inflation Protected Securities, commodities, and REITs may be used to further enhance diversification while offering opportunities for return.  In accordance with ERISA guidelines, common stock of the Company may be purchased up to 10% of the fair market value of the Plan’s assets at the time of acquisition.  Derivative investments are prohibited in the plan.
The return on assets assumption was developed through review of historical market returns, historical asset class volatility and correlations, current market conditions, the Plan’s past experience, and expectations on potential future market returns. The assumption represents a long-term average view of the performance of the assets in the Plan, a return that may or may not be achieved during any one calendar year. The assumption is based on the return of the Plan using the historical 15 year return adjusted for the potential for lower than historical returns due to low interest rates, and an expected modest recovery in global economic growth as a result of the deep recession.
Cash Flows - We were not required to make any contribution to our qualified pension plan in 2014.    Arrow makes contributions for its postretirement benefits in an amount equal to actual expenses for the year.

Other_Expenses

Other Expenses	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Schedule of Other Operating Cost and Expense, by Component [Table Text Block]	OTHER EXPENSES (Dollars In Thousands)
	Other operating expenses included in the consolidated statements of income are as follows:
		2014		2013		2012
	Computer Services	$	3,659	$	3,261	$	2,263
	Legal and Other Professional Fees	1,836		1,823		1,962
	Postage and Courier	1,084		1,046		1,040
	Stationery and Printing	851		905		975
	Advertising and Promotion	886		879		831
	Telephone and Communications	746		804		808
	Intangible Asset Amortization	387		452		518
	All Other	3,531		3,486		3,243
	Total Other Operating Expense	$	12,980	$	12,656	$	11,640

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	INCOME TAXES (Dollars In Thousands)
	The provision for income taxes is summarized below:
	Current Tax Expense:	2014			2013			2012
	Federal	$	9,270		$	7,933		$	8,763
	State	1,203			852			1,251
	Total Current Tax Expense	10,473			8,785			10,014
	Deferred Tax Expense (Benefit):
	Federal	(315		)	172			(290		)
	State	16			122			(63		)
	Total Deferred Tax Expense (Benefit)	(299		)	294			(353		)
	Total Provision for Income Taxes	$	10,174		$	9,079		$	9,661
	The provisions for income taxes differed from the amounts computed by applying the U.S. Federal Income Tax Rate of 35% for 2014, 2013 and 2012 to pre-tax income as a result of the following:
		2014			2013			2012
	Computed Tax Expense at Statutory Rate	$	11,737		$	10,806		$	11,144
	Increase (Decrease) in Income Taxes Resulting From:
	Tax-Exempt Income	(2,215		)	(2,238		)	(2,132		)
	Nondeductible Interest Expense	51			80			95
	State Taxes, Net of Federal Income Tax Benefit	791			633			814
	Other Items, Net	(190		)	(202		)	(260		)
	Total Provision for Income Taxes	$	10,174		$	9,079		$	9,661
	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2014 and 2013 are presented below:
		2014			2013
	Deferred Tax Assets:
	Allowance for Loan Losses	$	6,113		$	5,794
	Pension and Deferred Compensation Plans	3,885			3,999
	Pension Liability Included in Accumulated Other Comprehensive Income	6,263			4,426
	Other	614			566
	Total Gross Deferred Tax Assets	16,875			14,785
	Valuation Allowance for Deferred Tax Assets	—			—
	Total Gross Deferred Tax Assets, Net of Valuation Allowance	$	16,875		$	14,785
	Deferred Tax Liabilities:
	Pension Plans	$	7,604		$	7,724
	Depreciation	1,222			1,561
	Deferred Income	3,927			3,526
	Net Unrealized Gains on Securities Available-for-Sale Included in	1,638			1,557
	Accumulated Other Comprehensive Income
	Goodwill	5,242			5,230
	Total Gross Deferred Tax Liabilities	$	19,633		$	19,598
	Management believes that the realization of the recognized net deferred tax assets at December 31, 2014 and 2013 is more likely than not, based on existing loss carryback ability, available tax planning strategies and expectations as to future taxable income.
	Interest and penalties are recorded as a component of the provision for income taxes, if any.  Tax years 2011 through 2014 are subject to Federal examination. Tax years 2013 and 2014 are subject to New York State examination. Tax years 2010 to 2012 are currently under New York State examination. We do not expect any material changes to our provisions for state taxes for those years as a result of the examination.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	EARNINGS PER SHARE (In Thousands, Except Per Share Amounts)
	The following table presents a reconciliation of the numerator and denominator used in the calculation of basic and diluted earnings per common share ("EPS") for each of the years in the three-year period ended December 31, 2014.  All share and per share amounts have been adjusted for the 2014 2% stock dividend.
	Earnings Per Share
		Year-to-Date Period Ended:
		12/31/14		12/31/13		12/31/12
	Earnings Per Share - Basic:
	Net Income	$	23,360	$	21,795	$	22,179
	Weighted Average Shares - Basic	12,604		12,542		12,492
	Earnings Per Share - Basic	$	1.85	$	1.74	$	1.78
	Earnings Per Share - Diluted:
	Net Income	$	23,360	$	21,795	$	22,179
	Weighted Average Shares - Basic	12,604		12,542		12,492
	Dilutive Average Shares Attributable to Stock Options	29		31		10
	Weighted Average Shares - Diluted	12,633		12,573		12,502
	Earnings Per Share - Diluted	$	1.85	$	1.73	$	1.77
	Antidilutive Shares Excluded from the Calculation	—		47		203
	of Earnings Per Share

Fair_Values

Fair Values	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	FAIR VALUES (Dollars In Thousands)
	FASB ASC Subtopic 820-10 defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles (GAAP) and requires certain disclosures about fair value measurements.  We do not have any nonfinancial assets or liabilities measured at fair value on a recurring basis. The only assets or liabilities that Arrow measured at fair value on a recurring basis at December 31, 2014 and 2013 were securities available-for-sale.  Arrow held no securities or liabilities for trading on such date.  For information on fair value measurements, including descriptions of level 1, 2 and 3 of the fair value hierarchy and the valuation methods employed by Arrow, see Note 2 - “Summary of Significant Accounting Policies.”
	The table below presents the financial instrument's fair value and the amounts within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement:
	Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis
		Fair Value Measurements at Reporting Date Using:
	Fair Value of Assets and Liabilities Measured on a Recurring Basis:	Fair Value		Quoted Prices		Significant Other		Significant Unobservable Inputs		Total Gains (Losses)
				In Active Markets for Identical Assets		Observable Inputs		(Level 3)
				(Level 1)		(Level 2)
	December 31, 2014
	Securities Available-for Sale:
	U.S. Agency Obligations	$	137,603	$	—	$	137,603	$	—
	State and Municipal Obligations	81,730		—		81,730		—
	Mortgage-Backed Securities - Residential	128,827		—		128,827		—
	Corporate and Other Debt Securities	16,725		—		16,725		—
	Mutual Funds and Equity Securities	1,254		—		1,254		—
	Total Securities Available-for-Sale	$	366,139	$	—	$	366,139	$	—
	December 31, 2013
	Securities Available-for Sale:
	U.S. Agency Obligations	$	136,475	$	—	$	136,475	$	—
	State and Municipal Obligations	127,389		—		127,389		—
	Mortgage-Backed Securities - Residential	175,778		—		175,778		—
	Corporate and Other Debt Securities	16,798		—		16,798		—
	Mutual Funds and Equity Securities	1,166		—		1,166		—
	Total Securities Available-for Sale	$	457,606	$	—	$	457,606	$	—
	Fair Value of Assets and Liabilities Measured on a Nonrecurring Basis:
	December 31, 2014
	Collateral Dependent Impaired Loans	$	574	$	—	$	—	$	574	$	(109	)
	Other Real Estate Owned and Repossessed Assets, Net	$	393	$	—	$	—	$	393	$	(15	)
	December 31, 2013
	Other Real Estate Owned and Repossessed Assets, Net	$	144	$	—	$	—	$	144	$	(79	)
	We determine the fair value of financial instruments under the following hierarchy:
	•	Level 1 - Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	•	Level 2 - Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability;
	•	Level 3 - Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	Fair Value Methodology for Assets and Liabilities Measured on a Recurring Basis
	The fair value of level 1 securities available-for-sale are based on unadjusted, quoted market prices from exchanges in active markets. The fair value of level 2 securities available-for-sale are based on an independent bond and equity pricing service for identical assets or significantly similar securities and an independent equity pricing service for equity securities not actively traded. The pricing services use a variety of techniques to arrive at fair value including market maker bids, quotes and pricing models. Inputs to the pricing models include recent trades, benchmark interest rates, spreads and actual and projected cash flows.
	Fair Value Methodology for Assets and Liabilities Measured on a Nonrecurring Basis
	The fair value of collateral dependent impaired loans and other real estate owned was based on third-party appraisals. The appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses.
	Other assets which might have been included in this table include mortgage servicing rights, goodwill and other intangible assets. Arrow evaluates each of these assets for impairment on an annual basis, with no impairment recognized for these assets at December 31, 2014 and December 31, 2013.
	Fair Value by Balance Sheet Grouping
	The following table presents a summary of the carrying amount, the fair value or an amount approximating fair value and the fair value hierarchy of Arrow’s financial instruments:
	Schedule of Fair Values by Balance Sheet Grouping
						Fair Value Hierarchy
		Carrying		Fair		Level 1		Level 2		Level 3
		Amount		Value
	December 31, 2014
	Cash and Cash Equivalents	$	46,295	$	46,295	$	46,295	$	—	$	—
	Securities Available-for-Sale	366,139		366,139		—		366,139		—
	Securities Held-to-Maturity	302,024		308,566		—		308,566		—
	Federal Home Loan Bank and Federal Reserve Bank Stock	4,851		4,851		4,851		—		—
	Net Loans	1,397,698		1,405,454		—		—		1,405,454
	Accrued Interest Receivable	5,834		5,834		5,834		—		—
	Deposits	1,902,948		1,899,682		1,697,105		202,577		—
	Federal Funds Purchased and Securities Sold Under Agreements to Repurchase	19,421		19,421		19,421		—		—
	Federal Home Loan Bank Term Advances	51,000		51,258		41,000		10,258		—
	Junior Subordinated Obligations Issued	20,000		20,000		—		20,000		—
	to Unconsolidated Subsidiary Trusts
	Accrued Interest Payable	274		274		274		—		—
	December 31, 2013
	Cash and Cash Equivalents	$	49,980	$	49,980	$	49,980	$	—	$	—
	Securities Available-for-Sale	457,606		457,606		—		457,606		—
	Securities Held-to-Maturity	299,261		302,305		—		302,305		—
	Federal Home Loan Bank and Federal Reserve Bank Stock	6,281		6,281		6,281		—		—
	Net Loans	1,252,038		1,266,020		—		—		1,266,020
Accrued Interest Receivable	5,745		5,745		5,745		—		—
Deposits	1,842,330		1,839,613		1,595,103		244,510		—
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase	11,777		11,777		11,777		—		—
Federal Home Loan Bank Term Advances	73,000		74,629		53,000		21,629		—
Junior Subordinated Obligations Issued	20,000		20,000		—		20,000		—
to Unconsolidated Subsidiary Trusts
Accrued Interest Payable	439		439		439		—		—
Fair Value Methodology for Financial Instruments Not Measured on a Recurring or Nonrecurring Basis
Securities held-to-maturity are fair valued utilizing an independent bond pricing service for identical assets or significantly similar securities.  The pricing service uses a variety of techniques to arrive at fair value including market maker bids, quotes and pricing models.  Inputs to the pricing models include recent trades, benchmark interest rates, spreads and actual and projected cash flows.
Fair values for loans are estimated for portfolios of loans with similar financial characteristics.  Loans are segregated by type such as commercial, commercial real estate, residential mortgage, indirect and other consumer loans.  Each loan category is further segmented into fixed and adjustable interest rate terms and by performing and nonperforming categories.  The fair value methodology does not use an exit price methodology. The fair value of performing loans is calculated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect the credit and interest rate risk inherent in the loan.  The estimate of maturity is based on historical experience with repayments for each loan classification, modified, as required, by an estimate of the effect of current economic and lending conditions.   Fair value for nonperforming loans is generally based on recent external appraisals.  If appraisals are not available, estimated cash flows are discounted using a rate commensurate with the risk associated with the estimated cash flows.  Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information.
The fair value of time deposits is based on the discounted value of contractual cash flows, except that the fair value is limited to the extent that the customer could redeem the certificate after imposition of a premature withdrawal penalty.  The discount rates are estimated using the FHLBNY yield curve, which is considered representative of Arrow’s time deposit rates. The fair value of all other deposits is equal to the carrying value.
The fair value of FHLBNY advances is estimated based on the discounted value of contractual cash flows.  The discount rate is estimated using current rates on FHLBNY advances with similar maturities and call features.
Based on Arrow’s capital adequacy, the book value of the outstanding trust preferred securities (Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts) are considered to approximate fair value since the interest rates are variable (indexed to LIBOR) and Arrow is well-capitalized.

Leases

Leases	12 Months Ended
	Dec. 31, 2014
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Leases of Lessee Disclosure [Text Block]	LEASES (Dollars In Thousands)
	At December 31, 2014, Arrow was obligated under a number of noncancellable operating leases for buildings and equipment. Certain of these leases provide for escalation clauses and contain renewal options calling for increased rentals if the lease is renewed.
	Net rental expense for the years ended December 31, 2014, 2013 and 2012 was as follows:
		2014		2013		2012
	Net Rental Expense	$	784	$	671	$	597
	Future minimum lease payments on operating leases at December 31, 2014 were as follows:
		Operating
		Leases
	2015	$	686
	2016	483
	2017	389
	2018	318
	2019	266
	Later Years	372
	Total Minimum Lease Payments	$	2,514
	Arrow leases five of its branch offices, at market rates, from Stewart’s Shops Corp.  Mr. Gary C. Dake, President of Stewart’s Shops Corp., serves on both the boards of Arrow and Saratoga National Bank and Trust Company.

Regulatory_Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2014
Banking and Thrift [Abstract]
Regulatory Capital Requirements under Banking Regulations [Text Block]	REGULATORY MATTERS (Dollars in Thousands)
	In the normal course of business, Arrow and its subsidiaries operate under certain regulatory restrictions, such as the extent and structure of covered inter-company borrowings and maintenance of reserve requirement balances.
	The principal source of the funds for the payment of stockholder dividends by Arrow has been from dividends declared and paid to Arrow by its bank subsidiaries.  As of December 31, 2014, the maximum amount that could have been paid by subsidiary banks to Arrow, without prior regulatory approval, was approximately $29.2.
	Under current Federal Reserve regulations, Arrow is prohibited from borrowing from the subsidiary banks unless such borrowings are secured by specific obligations.  Additionally, the maximum of any such borrowing is limited to 10% of an affiliate’s capital and surplus.
	Arrow and its subsidiary banks are subject to various regulatory capital requirements administered by the federal banking agencies.  Failure to meet minimum capital requirements can initiate certain mandatory--and possibly additional discretionary--actions by regulators that, if undertaken, could have a direct material effect on an institution’s financial statements.  Under capital adequacy guidelines and the regulatory framework for prompt corrective action, Arrow and its subsidiary banks must meet specific capital guidelines that involve quantitative measures of assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices.  Capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors.
	Quantitative measures established by regulation to ensure capital adequacy require Arrow and its subsidiary banks to maintain minimum capital amounts and ratios (set forth in the table below) of total and Tier I capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier I capital (as defined) to average assets (as defined).  Management believes, as of December 31, 2014 and 2013, that Arrow and both subsidiary banks meet all capital adequacy requirements to which they are subject.
	As of December 31, 2014, Arrow and both subsidiary banks qualified as well-capitalized under the regulatory framework for prompt corrective action.  To be categorized as “well-capitalized,” Arrow and its subsidiary banks must maintain minimum total risk-based, Tier I risk-based, and Tier I leverage ratios as set forth in the table below.  There are no conditions or events that management believes have changed Arrow’s or its subsidiary banks’ categories.
	Arrow’s and its subsidiary banks’, Glens Falls National Bank and Trust Company (“Glens Falls National”) and Saratoga National Bank and Trust Company (“Saratoga National”), actual capital amounts and ratios are presented in the table below as of December 31, 2014 and 2013:
		Actual				Minimum Amounts For Capital Adequacy Purposes						Minimum Amounts To Be Well-Capitalized
		Amount		Ratio		Amount			Ratio			Amount				Ratio
	As of December 31, 2014:
	Total Capital
	(to Risk Weighted Assets):
	Arrow	$	225,766	15.5	%	$	116,524		8	%		$	145,655			10	%
	Glens Falls National	183,446		15.5	%	94,682			8	%		118,352				10	%
	Saratoga National	35,217		13.3	%	21,183			8	%		26,479				10	%
	Tier I Capital
	(to Risk Weighted Assets):
	Arrow	210,136		14.5	%	57,969			4	%		86,953				6	%
	Glens Falls National	170,497		14.4	%	47,360			4	%		71,040				6	%
	Saratoga National	32,596		12.3	%	10,600			4	%		15,900				6	%
	Tier I Capital
	(to Average Assets):
	Arrow	210,136		9.4	%	89,420			4	%		89,420				4	%
	Glens Falls National	170,497		9.1	%	74,944			4	%		93,680				5	%
	Saratoga National	32,596		9.4	%	13,871			4	%		17,338				5	%
		Actual				Minimum Amounts For Capital					Minimum Amounts To Be Well-Capitalized
						Adequacy Purposes
		Amount		Ratio		Amount		Ratio			Amount			Ratio
	As of December 31, 2013:
	Total Capital
	(to Risk Weighted Assets):
	Arrow	$	212,360	15.8	%	107,524		8	%		134,405			10	%
	Glens Falls National	172,720		15.4	%	89,725		8	%		112,156			10	%
	Saratoga National	33,396		14.8	%	18,052		8	%		22,565			10	%
	Tier I Capital
	(to Risk Weighted Assets):
	Arrow	197,906		14.7	%	53,852		4	%		80,778			6	%
	Glens Falls National	160,849		14.4	%	44,680		4	%		67,020			6	%
	Saratoga National	30,833		13.7	%	9,002		4	%		13,504			6	%
	Tier I Capital
	(to Average Assets):
	Arrow	197,906		9.2	%	86,046		4	%		86,046			4	%
	Glens Falls National	160,849		8.8	%	73,113		4	%		91,391			5	%
	Saratoga National	30,833		9.7	%	12,715		4	%		15,893			5	%

Parent_Only_Financial_Informat

Parent Only Financial Information	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	PARENT ONLY FINANCIAL INFORMATION (Dollars In Thousands)
	Condensed financial information for Arrow Financial Corporation is as follows:
	BALANCE SHEETS	December 31,
	ASSETS	2014			2013
	Interest-Bearing Deposits with Subsidiary Banks	$	3,013		$	3,349
	Available-for-Sale Securities	1,254			1,166
	Held-to-Maturity Securities	1,000			1,000
	Investment in Subsidiaries at Equity	214,813			206,680
	Other Assets	6,538			5,807
	Total Assets	$	226,618		$	218,002
	LIABILITIES
	Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	$	20,000		$	20,000
	Other Liabilities	5,692			5,848
	Total Liabilities	25,692			25,848
	STOCKHOLDERS’ EQUITY
	Total Stockholders’ Equity	200,926			192,154
	Total Liabilities and Stockholders’ Equity	$	226,618		$	218,002
	STATEMENTS OF INCOME	Years Ended December 31,
	Income:	2014			2013			2012
	Dividends from Bank Subsidiaries	$	13,300		$	12,900		$	12,700
	Interest and Dividends on Investments	116			116			123
	Other Income (Including Management Fees)	578			549			776
	Net Gains on Securities Transactions	—			—			63
	Total Income	13,994			13,565			13,662
	Expense:
	Interest Expense	620			640			692
	Salaries and Employee Benefits	77			59			75
	Other Expense	754			860			957
	Total Expense	1,451			1,559			1,724
	Income Before Income Tax Benefit and Equity
	in Undistributed Net Income of Subsidiaries	12,543			12,006			11,938
	Income Tax Benefit	473			634			575
	Equity in Undistributed Net Income of Subsidiaries	10,344			9,155			9,666
	Net Income	$	23,360		$	21,795		$	22,179
	The Statement of Changes in Stockholders’ Equity is not reported because it is identical to the Consolidated Statement of Changes in Stockholders’ Equity.
	STATEMENTS OF CASH FLOWS	Years Ended December 31,
		2014			2013			2012
	Cash Flows from Operating Activities:
	Net Income	$	23,360		$	21,795		$	22,179
	Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
	Undistributed Net Income of Subsidiaries	(10,344		)	(9,155		)	(9,666		)
	Net Gains on the Sale of Securities Available-for-Sale	—			—			(63		)
	Shares Issued Under the Directors’ Stock Plan	197			198			175
	Stock-Based Compensation Expense	360			372			424
	Changes in Other Assets and Other Liabilities	(1,014		)	(990		)	(1,640		)
	Net Cash Provided by Operating Activities	12,559			12,220			11,409
	Cash Flows from Investing Activities:
	Proceeds from the Sale of Securities Available-for-Sale	45			45			681
	Purchases of Securities Available-for-Sale	(45		)	(45		)	(359		)
	Net Cash Provided by Investing Activities	—			—			322
	Cash Flows from Financing Activities:
	Stock Options Exercised	1,942			1,254			2,105
	Shares Issued Under the Employee Stock Purchase Plan	—			477			484
	Shares Issued for Dividend Reinvestment Plans	—			1,280			1,822
	Tax Benefit for Exercises of Stock Options	25			23			68
	Purchase of Treasury Stock	(2,455		)	(1,709		)	(4,877		)
	Cash Dividends Paid	(12,407		)	(12,109		)	(11,815		)
	Net Cash Used in Financing Activities	(12,895		)	(10,784		)	(12,213		)
	Net (Decrease) Increase in Cash and Cash Equivalents	(336		)	1,436			(482		)
	Cash and Cash Equivalents at Beginning of the Year	3,349			1,913			2,395
	Cash and Cash Equivalents at End of the Year	$	3,013		$	3,349		$	1,913
	Supplemental Disclosures to Statements of
	Cash Flow Information:
	Interest Paid	$	620		$	640		$	692
Non-cash Investing and Financing Activities:
Shares Issued for Acquisition of Subsidiary	91			233			233

Summary_of_Significant_Account1

Summary of Significant Accounting Policies Significant Accounting (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation [Text Block]	Principles of Consolidation - The financial statements of Arrow and its wholly owned subsidiaries are consolidated and all material inter-company transactions have been eliminated.  In the “Parent Company Only” financial statements in Note 20, the investment in wholly owned subsidiaries is carried under the equity method of accounting.  When necessary, prior years’ consolidated financial statements have been reclassified to conform to the current-year financial statement presentation.
	The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity under GAAP. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. The Company consolidates voting interest entities in which it has all, or at least a majority of, the voting interest. As defined in applicable accounting standards, variable interest entities (VIE) are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when the Company has both the power and ability to direct the activities of the VIE that most significantly impact the VIE's economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Company’s wholly owned subsidiaries Arrow Capital Statutory Trust II and Arrow Capital Statutory Trust III are VIEs for which the Company is not the primary beneficiary. Accordingly, the accounts of these entities are not included in the Company’s consolidated financial statements.
Segment Reporting [Policy Text Block]	Segment Reporting - Arrow operations are primarily in the community banking industry, which constitutes Arrow’s only segment for financial reporting purposes.  Arrow provides other services, such as trust administration, retirement plan administration, advice to our proprietary mutual funds and insurance products, but these services do not rise to the quantitative thresholds for separate disclosure.  Arrow operates primarily in the northeastern region of New York State in Warren, Washington, Saratoga, Essex, Clinton and Albany counties and surrounding areas.
Cash and Cash Equivalents [Policy Text Block]	Cash and Cash Equivalents - Cash and cash equivalents include the following items:  cash at branches, due from bank balances, cash items in the process of collection, interest-bearing bank balances and federal funds sold.
Securities [Policy Text Block]	Securities - Management determines the appropriate classification of securities at the time of purchase.  Securities reported as held-to-maturity are those debt securities which Arrow has both the positive intent and ability to hold to maturity and are stated at amortized cost.  Securities available-for-sale are reported at fair value, with unrealized gains and losses reported in accumulated other comprehensive income or loss, net of taxes.  Realized gains and losses are based upon the amortized cost of the specific security sold.  A decline in the fair value of any available-for-sale or held-to-maturity security below cost that is deemed to be other-than-temporary results in an impairment to reduce the carrying amount to fair value.  To determine whether an impairment is other-than-temporary, we consider all available information relevant to the collectibility of the security, including past events, current conditions, and reasonable and supportable forecasts when developing an estimate of cash flows expected to be collected.  Evidence considered in this assessment includes the reasons for impairment, the severity and duration of the impairment, changes in value subsequent to year-end, forecasted performance of the investee, and the general market condition in the geographic area or industry the investee operates in.  When an other-than-temporary impairment has occurred on a debt security, the amount of the other-than-temporary impairment recognized in earnings depends on whether we intend to sell the debt security or more likely than not will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss.  If we intend to sell the debt security or it is more likely than not that we will be required to sell the debt security before recovery of its amortized cost basis less any current-period credit loss, the other-than-temporary impairment is recognized in earnings equal to the entire difference between the investment’s amortized cost basis and its fair value at the balance sheet date.  If we do not intend to sell the debt security and it is not more likely than not that we will be required to sell the debt security before recovery of its amortized cost basis, the other-than-temporary impairment is separated into the amount representing the credit loss and the amount related to all other factors.  The amount of the total other-than-temporary impairment related to the credit loss is recognized in earnings.  The amount of the total other-than-temporary impairment related to other factors is recognized in other comprehensive income, net of applicable income taxes.
Loans and Allowance for Loan Losses [Policy Text Block]	Loans and Allowance for Loan Losses - Interest income on loans is accrued and credited to income based upon the principal amount outstanding.  Loan fees and costs directly associated with loan originations are deferred and amortized/accreted as an adjustment to yield over the lives of the loans originated.
	From time-to-time, Arrow has sold (most with servicing retained) residential real estate loans at or shortly after origination.  Any gain or loss on the sale of loans, along with the value of the servicing right, is recognized at the time of sale as the difference between the recorded basis in the loan and net proceeds from the sale.  Loans held for sale are recorded at the lower of cost or fair value on an aggregate basis.
	Loans are placed on nonaccrual status either due to the delinquency status of principal and/or interest or a judgment by management that the full repayment of principal and interest is unlikely. Unless already placed on nonaccrual status, loans secured by home equity lines of credit are put on nonaccrual status when 120 days past due; residential real estate loans when 150 days past due; commercial and commercial real estate loans are evaluated on a loan-by-loan basis and are placed on nonaccrual status when 90 days past due if the full collection of principal and interest is uncertain. The balance of any accrued interest deemed uncollectible at the date the loan is placed on nonaccrual status is reversed, generally against interest income.  A loan is returned to accrual status at the later of the date when the past due status of the loan falls below the threshold for nonaccrual status or management deems that it is likely that the borrower will repay all interest and principal.  For payments received while the loan is on nonaccrual status, we may recognize interest income on a cash basis if the repayment of the remaining principal and accrued interest is deemed likely.
	The allowance for loan losses is maintained by charges to operations based upon our best estimate of the probable amount of loans that we will be unable to collect based on current information and events.  Provisions to the allowance for loan losses are offset by actual loan charge-offs (net of any recoveries).  We evaluate the loan portfolio for potential charge-offs on a monthly basis.  In general, automobile and other consumer loans are charged-off when 120 days delinquent.  Residential real estate loans are charged-off when a loss becomes known or based on a new appraisal at the earlier of 180 days past due or repossession.  Commercial and commercial real estate loans loans are evaluated early in their delinquency status and are charged-off when management concludes that not all principal will be repaid from on-going cash flows or liquidation of collateral. An evaluation of estimated proceeds from the liquidation of the loan’s collateral is compared to the loan carrying amount and a charge to the allowance for loan losses is taken for any deficiency.  While management uses available information to recognize losses on loans, future additions to the allowance may be necessary based on changes in economic conditions in Arrow's market area.  In addition, various Federal regulatory agencies, as an integral part of their examination process, review Arrow's allowance for loan losses. Such agencies may require Arrow to recognize additions to the allowance in future periods, based on their judgments about information available to them at the time of their examination, which may not be currently available to management.
	We consider nonaccrual loans over $250 thousand and all troubled debt restructured loans to be impaired loans and we evaluate these loans individually to determine the amount of impairment, if any. The amount of impairment, if any, related to individual impaired loans is measured based on either the present value of expected future cash flows discounted at the loan's effective interest rate, the loan's observable market price or the fair value of the collateral if the loan is collateral dependent. Arrow determines impairment for collateral dependent loans based on the fair value of the collateral less estimated costs to sell. Any excess of the recorded investment in the collateral dependent impaired loan over the estimated collateral value, less costs to sell, is typically charged off. For impaired loans which are not collateral dependent, impairment is measured by comparing the recorded investment in the loan to the present value of the expected cash flows, discounted at the loan’s effective interest rate.  If this amount is less than the recorded investment in the loan, an impairment reserve is recognized as part of the allowance for loan losses, or based upon the judgment of management all or a portion of the excess of the recorded investment in the loan over the present value of the estimated future cash flow may be charged off.
	The allowance for loan losses on the remaining loans is primarily determined based upon consideration of the historical net loss experience of the respective portfolios that have occurred within each pool of loans over the loss emergence period (LEP), adjusted as necessary based upon consideration of qualitative considerations impacting the inherent risk of loss in the respective loan portfolios. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is recognized in the financial statements. Since the LEP may change under various economic environments, we update the LEP calculation on a semiannual basis.
	In management’s opinion, the balance of the allowance for loan losses, at each balance sheet date, is sufficient to provide for probable loan losses inherent in the corresponding loan portfolio.
Other Real Estate Owned and Repossessed Assets [Policy Text Block]	Other Real Estate Owned and Repossessed Assets - Real estate acquired by foreclosure and assets acquired by repossession are recorded at the fair value of the property less estimated costs to sell at the time of repossession.  Subsequent declines in fair value, after transfer to other real estate owned and repossessed assets are recognized through a valuation allowance. Such declines in fair value along with related operating expenses to administer such properties or assets are charged directly to operating expense.
Premises and Equipment [Policy Text Block]	Premises and Equipment - Premises and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization included in operating expenses are computed largely on the straight-line method. Depreciation is based on the estimated useful lives of the assets (buildings and improvements 20-40 years; furniture and equipment 7-10 years; data processing equipment 5-7 years) and, in the case of leasehold improvements, amortization is computed over the terms of the respective leases or their estimated useful lives, whichever is shorter.  Gains or losses on disposition are reflected in earnings.
Income Taxes [Policy Text Block]	Income Taxes - Arrow accounts for income taxes under the asset and liability method.  Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases.  Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income tax expense in the period that includes the enactment date.  Arrow’s policy is that deferred tax assets are reduced by a valuation allowance if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.
Goodwill and Other Intangible Assets [Policy Text Block]	Goodwill and Other Intangible Assets - Identifiable intangible assets acquired in a business combination are capitalized and amortized.  Any remaining unidentifiable intangible asset is classified as goodwill, for which amortization is not required but which must be evaluated for impairment.  Arrow tests for impairment of goodwill on an annual basis, or when events and circumstances indicate potential impairment.  In evaluating goodwill for impairment, Arrow first assesses certain qualitative factors to determine if it is more likely than not that the fair value of the reporting unit is less than its carrying value. If it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is considered not impaired. If the carrying amount of a reporting unit exceeds its fair value, the second step of the goodwill impairment test is performed to measure the amount of impairment loss, if any.
	The carrying amounts of other recognized intangible assets that meet recognition criteria and for which separate accounting records have been maintained (core deposit intangibles and mortgage servicing rights), have been included in the consolidated balance sheet as “Other Intangible Assets, Net.”  Core deposit intangibles are being amortized on a straight-line basis over a period of ten to fifteen years.
	Arrow has sold residential real estate loans, primarily to Freddie Mac, with servicing retained.   Mortgage servicing rights are recognized as an asset when loans are sold with servicing retained, by allocating the cost of an originated mortgage loan between the loan and servicing right based on estimated relative fair values.  The cost allocated to the servicing right is capitalized as a separate asset and amortized in proportion to, and over the period of, estimated net servicing income.  Capitalized mortgage servicing rights are evaluated for impairment by comparing the asset’s carrying value to its current estimated fair value.  Fair values are estimated using a discounted cash flow approach, which considers future servicing income and costs, current market interest rates, and anticipated prepayment, and default rates.  Impairment losses are recognized through a valuation allowance for servicing rights having a current fair value that is less than amortized cost on an aggregate basis.  Adjustments to increase or decrease the valuation allowance are charged or credited to income as a component of other operating income.
Pension and Postretirement Benefits [Policy Text Block]	Pension and Postretirement Benefits - Arrow maintains a non-contributory, defined benefit pension plan covering substantially all employees, a supplemental pension plan covering certain executive officers selected by the Board of Directors, and certain post-retirement medical, dental and life insurance benefits for employees and retirees.  The costs of these plans, based on actuarial computations of current and future benefits for employees, are charged to current operating expenses. The cost of post-retirement benefits other than pensions is recognized on an accrual basis as employees perform services to earn the benefits.  Arrow recognizes the overfunded or underfunded status of our single employer defined benefit pension plan as an asset or liability on its consolidated balance sheet and recognizes changes in the funded status in comprehensive income in the year in which the change occurred.
	Prior service costs or credits are amortized on a straight-line basis over the average remaining service period of active participants.  Gains and losses in excess of 10% of the greater of the benefit obligation or the fair value of assets are amortized over the average remaining service period of active participants.
	The discount rate assumption is determined by preparing an analysis of the respective plan’s expected future cash flows and high-quality fixed-income investments currently available and expected to be available during the period to maturity of the pension benefits.
Share-Based Compensation Plans [Policy Text Block]	Stock-Based Compensation Plans - Arrow has two stock option plans, which are described more fully in Note 12.  The Company expenses the grant date fair value of options granted.  The expense is recognized over the vesting period of the grant, typically four years, on a straight-line basis. Shares are generally issued from treasury for the exercise of stock options.
	Arrow sponsors an Employee Stock Purchase Plan ("ESPP") under which employees may purchase Arrow’s common stock at a 5% discount below market price at the time of purchase. This stock purchase plan is not considered a compensatory plan.
	Arrow sponsors an Employee Stock Ownership Plan ("ESOP"), a qualified defined contribution plan.   The ESOP has borrowed funds from one of Arrow’s subsidiary banks to purchase Arrow common stock.  The shares pledged as collateral are reported as a reduction of Arrow’s stockholders’ equity.  Compensation expense is recognized as shares are released for allocation to individual employee accounts equal to the current average market price.
Securities Sold Under Agreements to Repurchase [Policy Text Block]	Securities Sold Under Agreements to Repurchase - In securities repurchase agreements, Arrow receives cash from a counterparty in exchange for the transfer of securities to a third party custodian’s account that explicitly recognizes Arrow’s interest in the securities.  These agreements are accounted for by Arrow as secured financing transactions, since it maintains effective control over the transferred securities, and meets other criteria for such accounting.  Accordingly, the cash proceeds are recorded as borrowed funds, and the underlying securities continue to be carried in Arrow’s securities available-for-sale portfolio.
Earnings Per Share [Policy Text Block]	Earnings Per Share (“EPS”) - Basic EPS excludes dilution and is computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period.  Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity (such as Arrow’s stock options), computed using the treasury stock method.  Unallocated common shares held by Arrow’s Employee Stock Ownership Plan are not included in the weighted average number of common shares outstanding for either the basic or diluted EPS calculation.
Financial Instruments [Policy Text Block]	Financial Instruments - Arrow is a party to certain financial instruments with off-balance sheet risk, such as:  commercial lines of credit, construction lines of credit, overdraft protection, home equity lines of credit and standby letters of credit.  Arrow's policy is to record such instruments when funded.  Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument.  These estimates do not reflect any premium or discount that could result from offering for sale at one time Arrow's entire holdings of a particular financial instrument.  Because no market exists for a significant portion of Arrow's financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors.  These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision.  Changes in assumptions could significantly affect the estimates.
	Fair value estimates are based on existing on- and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments.  For example, Arrow has a trust department that contributes net fee income annually.  The value of trust department customer relationships is not considered a financial instrument of the Company, and therefore this value has not been incorporated into the fair value estimates. Other significant assets and liabilities that are not considered financial assets or liabilities include deferred taxes, premises and equipment, the value of low-cost, long-term core deposits and goodwill.  In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in any of the estimates.
	The carrying amount of the following short-term assets and liabilities is a reasonable estimate of fair value: cash and due from banks, federal funds sold and purchased, securities sold under agreements to repurchase, demand deposits, savings, N.O.W. and money market deposits, other short-term borrowings, accrued interest receivable and accrued interest payable.  The fair value estimates of other on- and off-balance sheet financial instruments, as well as the method of arriving at fair value estimates, are included in the related footnotes and summarized in Note 17.
	Fair Value Measures - We determine the fair value of financial instruments under the following hierarchy:
	•	Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;
	•	Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability;
	•	Level 3 – Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).
	A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement.
Management's Use of Estimates [Policy Text Block]	Management’s Use of Estimates -The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of income and expenses during the reporting period.  Our most significant estimates are the allowance for loan losses, the evaluation of other-than-temporary impairment of investment securities, goodwill impairment, pension and other postretirement liabilities, analysis of a need for a valuation allowance for deferred tax assets and other fair value calculations. Actual results could differ from those estimates.
	A material estimate that is particularly susceptible to significant change in the near term is the allowance for loan losses.  In connection with the determination of the allowance for loan losses, management obtains appraisals for properties.  The allowance for loan losses is management’s best estimate of probable loan losses incurred as of the balance sheet date.  While management uses available information to recognize losses on loans, future adjustments to the allowance for loan losses may be necessary based on changes in economic conditions.
Recent Accounting Pronouncements [Policy Text Block]	Recent Accounting Pronouncements
	During 2014 the FASB issued eighteen accounting standards updates and, through the date of this report, one additional update in 2015. For those updates that apply to Arrow, the following paragraphs provide a brief description, the effective date and the estimated impact on our financial condition or results of operations.
	ASU 2014-01 "Investments-Equity Method and Joint Ventures" allows an entity that invests in affordable housing projects that qualify for low-income housing tax credits to make an accounting policy election to account for their investments in qualified affordable housing projects using the proportional amortization method if certain conditions are met. Under the proportional amortization method, an entity amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received and recognizes the net investment performance in the income statement as a component of income tax expense. The standard is effective for annual years beginning after December 15, 2014, with earlier adoption allowed. We are evaluating the impact of adopting this election and do not expect that this will have a material impact on our financial condition or results of operations.
	ASU 2014-04 "Receivables - Trouble Debt Restructurings by Creditors" provides additional guidance on when an in substance repossession or foreclosure occurs and is effective for annual periods beginning after December 15, 2014. We are evaluating the impact of adopting this standard, and we do not expect that it will have a material impact on our financial condition or results of operations.
	ASU 2014-14 "Receivables - Trouble Debt Restructurings by Creditors - Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure" requires an entity to report a separate other receivable for the amount of the expected guarantee upon foreclosure. For Arrow, the standard is effective for the first quarter of 2015. The adoption will not have a material impact on our financial condition or results of operations.
	ASU 2015-01 "Income Statement - Extraordinary and Unusual Items" eliminates the concept of extraordinary items.

Cash_and_Cash_Equivalents_Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table is the schedule of cash and cash equivalents at December 31, 2014 and 2013:
		2014		2013
	Cash and Due From Banks	$	35,081	$	37,275
	Interest-Bearing Deposits at Banks	11,214		12,705
	Total Cash and Cash Equivalents	$	46,295	$	49,980
	Supplemental Information:
	Total required reserves, including vault cash and Federal Reserve Bank deposits	$	19,989	$	18,879

Investment_Securities_Tables

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities [Table Text Block]	The following table is the schedule of Available-For-Sale Securities at December 31, 2014 and 2013:
	Available-For-Sale Securities
			U.S. Agency			State and		Mortgage-		Corporate		Mutual Funds		Total
			Obligations			Municipal		Backed		and Other		and Equity		Available-
						Obligations		Securities -		Debt		Securities		For-Sale
								Residential		Securities				Securities
	December 31, 2014
	Available-For-Sale Securities,		$	137,540		$	81,582	$	124,732	$	16,988	$	1,120	$	361,962
	at Amortized Cost
	Available-For-Sale Securities,		137,603			81,730		128,827		16,725		1,254		366,139
	at Fair Value
	Gross Unrealized Gains		208			187		4,100		7		134		4,636
	Gross Unrealized Losses		145			39		5		270		—		459
	Available-For-Sale Securities,													267,384
	Pledged as Collateral
	Available-For-Sale Securities
			U.S. Agency			State and		Mortgage-		Corporate		Mutual Funds		Total
			Obligations			Municipal		Backed		and Other		and Equity		Available-
						Obligations		Securities -		Debt		Securities		For-Sale
								Residential		Securities				Securities
	Maturities of Debt Securities,
	at Amortized Cost:
	Within One Year		—			28,273		2,878		2,303				33,454
	From 1 - 5 Years		137,540			51,384		100,428		13,685				303,037
	From 5 - 10 Years		—			1,285		21,426		—				22,711
	Over 10 Years		—			640		—		1,000				1,640
	Maturities of Debt Securities,
	at Fair Value:
	Within One Year		—			28,329		2,888		2,307				33,524
	From 1 - 5 Years		137,603			51,476		103,786		13,618				306,483
	From 5 - 10 Years		—			1,285		22,153		—				23,438
	Over 10 Years		—			640		—		800				1,440
	Securities in a Continuous
	Loss Position, at Fair Value:
	Less than 12 Months		$	39,631		$	3,309	$	82	$	—	$	—	$	43,022
	12 Months or Longer		28,020			14,035		1,546		10,738		—		54,339
	Total		$	67,651		$	17,344	$	1,628	$	10,738	$	—	$	97,361
	Number of Securities in a		22			65		3		15		—		105
	Continuous Loss Position
	Unrealized Losses on
	Securities in a Continuous
	Loss Position:
	Less than 12 Months		$	48		$	—	$	—	$	—	$	—	$	48
	12 Months or Longer		97			39		5		270		—		411
	Total		$	145		$	39	$	5	$	270	$	—	$	459
	December 31, 2013
	Available-For-Sale Securities,		$	136,868		$	127,224	$	171,321	$	17,142	$	1,120	$	453,675
	at Amortized Cost
	Available-For-Sale Securities,		136,475			127,389		175,778		16,798		1,166		457,606
	at Fair Value
	Gross Unrealized Gains		2			306		4,714		10		46		5,078
	Gross Unrealized Losses		395			141		257		354		—		1,147
	Available-For-Sale Securities,													243,769
	Pledged as Collateral
	Securities in a Continuous
	Loss Position, at Fair Value:
	Less than 12 Months		$	60,664		$	29,967	$	15,190	$	7,375	$	—	$	113,196
	12 Months or Longer		33,849			4,597		11,841		6,063		—		56,350
	Total		$	94,513		$	34,564	$	27,031	$	13,438	$	—	$	169,546
	Number of Securities in a		26			107		13		19		—		165
	Continuous Loss Position
	Unrealized Losses on
	Securities in a Continuous
	Loss Position:
Less than 12 Months		$	336		$	120	$	108	$	92	$	—	$	656
12 Months or Longer		59			21		149		262		—		491
Total		$	395		$	141	$	257	$	354	$	—	$	1,147
Held-to-maturity Securities [Table Text Block]	The following table is the schedule of Held-To-Maturity Securities at December 31, 2014 and 2013:
	Held-To-Maturity Securities
			State and			Mortgage-		Corporate		Total
			Municipal			Backed		and Other		Held-To
			Obligations			Securities -		Debt		Maturity
						Residential		Securities		Securities
	December 31, 2014
	Held-To-Maturity Securities,		$	188,472		$	112,552	$	1,000	$	302,024
	at Amortized Cost
	Held-To-Maturity Securities,		193,252			114,314		1,000		308,566
	at Fair Value
	Gross Unrealized Gains		4,935			1,770		—		6,705
	Gross Unrealized Losses		155			8		—		163
	Held-To-Maturity Securities,									282,640
	Pledged as Collateral
	Maturities of Debt Securities,
	at Amortized Cost:
	Within One Year		34,163			—		—		34,163
	From 1 - 5 Years		88,866			36,649		—		125,515
	From 5 - 10 Years		63,394			75,903		—		139,297
	Over 10 Years		2,049			—		1,000		3,049
	Maturities of Debt Securities,
	at Fair Value:
	Within One Year		34,236			—		—		34,236
	From 1 - 5 Years		91,148			37,133		—		128,281
	From 5 - 10 Years		65,728			77,181		—		142,909
	Over 10 Years		2,140			—		1,000		3,140
	Securities in a Continuous
	Loss Position, at Fair Value:
	Less than 12 Months		$	2,143		$	4,581	$	—	$	6,724
	12 Months or Longer		16,033			—		—		16,033
	Total		$	18,176		$	4,581	$	—	$	22,757
	Number of Securities in a		74			1		—		75
	Continuous Loss Position
	Unrealized Losses on
	Securities in a Continuous
	Loss Position:
	Less than 12 Months		$	17		$	8	$	—	$	25
	12 Months or Longer		138			—		—		138
	Total		$	155		$	8	$	—	$	163
	December 31, 2013
	Held-To-Maturity Securities,		$	198,206		$	100,055	$	1,000	$	299,261
	at Amortized Cost
	Held-To-Maturity Securities,		202,390			98,915		1,000		302,305
	at Fair Value
	Gross Unrealized Gains		4,762			24		—		4,786
	Gross Unrealized Losses		578			1,164		—		1,742
	Held-To-Maturity Securities,									298,261
	Pledged as Collateral
	Held-To-Maturity Securities
			State and			Mortgage-		Corporate		Total
			Municipal			Backed		and Other		Held-To
			Obligations			Securities -		Debt		Maturity
						Residential		Securities		Securities
	Securities in a Continuous
	Loss Position, at Fair Value:
	Less than 12 Months		$	23,633		$	85,339	$	—	$	108,972
	12 Months or Longer		5,111			—		—		5,111
	Total		$	28,744		$	85,339	$	—	$	114,083
	Number of Securities in a		101			36		—		137
	Continuous Loss Position
	Unrealized Losses on
	Securities in a Continuous
	Loss Position:
Less than 12 Months		$	519		$	1,164	$	—	$	1,683
12 Months or Longer		59			—		—		59
Total		$	578		$	1,164	$	—	$	1,742
Schedule of Cost Method Investments [Table Text Block]	Schedule of Federal Reserve Bank and Federal Home Loan Bank Stock
	Federal Reserve Bank and Federal Home Loan Bank Stock are carried at cost.
		December 31,
		2014			2013
	Federal Reserve Bank Stock	$	1,048		$	1,035
	Federal Home Loan Bank Stock	3,803			5,246
	Total Federal Reserve Bank and Federal Home Loan Bank Stock	$	4,851		$	6,281

Loans_Tables

Loans (Tables)	12 Months Ended
	Dec. 31, 2014
Loans and Leases Receivable Disclosure [Abstract]
Past Due Financing Receivables [Table Text Block]	Loan Categories and Past Due Loans
	The following table presents loan balances outstanding as of December 31, 2014 and December 31, 2013 and an analysis of the recorded investment in loans that are past due at these dates.  Generally, Arrow considers a loan past due 30 or more days if the borrower is two or more payments past due.
	Schedule of Past Due Loans by Loan Category
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
	December 31, 2014
	Loans Past Due 30-59 Days	$	124		$	—		$	432		$	30		$	4,137		$	482		$	5,205
	Loans Past Due 60-89 Days	154			—			7			4			1,221			1,495			2,881
	Loans Past Due 90 or More Days	345			—			1,832			3			203			2,999			5,382
	Total Loans Past Due	623			—			2,271			37			5,561			4,976			13,468
	Current Loans	98,888			18,815			319,026			7,628			423,815			531,628			1,399,800
	Total Loans	$	99,511		$	18,815		$	321,297		$	7,665		$	429,376		$	536,604		$	1,413,268
	Loans 90 or More Days Past Due and Still Accruing Interest	$	—		$	—		$	—		$	—		$	—		$	537		$	537
	Nonaccrual Loans	$	473		$	—		$	2,071		$	4		$	411		$	3,940		$	6,899
	December 31, 2013
	Loans Past Due 30-59 Days	$	304		$	—		$	200		$	37		$	3,233		$	529		$	4,303
	Loans Past Due 60-89 Days	601			—			1,200			19			1,041			1,527			4,388
	Loans Past Due 90 or more Days	177			—			2,034			—			98			3,113			5,422
	Total Loans Past Due	1,082			—			3,434			56			4,372			5,169			14,113
	Current Loans	86,811			27,815			284,685			7,593			389,832			455,623			1,252,359
	Total Loans	$	87,893		$	27,815		$	288,119		$	7,649		$	394,204		$	460,792		$	1,266,472
	Loans 90 or More Days Past Due and Still Accruing Interest	$	28		$	—		$	—		$	—		$	—		$	624		$	652
	Nonaccrual Loans	$	352		$	—		$	2,048		$	—		$	219		$	3,860		$	6,479
Allowance for Credit Losses on Financing Receivables [Table Text Block]	Allowance for Loan Losses
	The following table presents a rollforward of the allowance for loan losses and other information pertaining to the allowance for loan losses:
	Allowance for Loan Losses
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Unallocated			Total
	Rollfoward of the Allowance for Loan Losses for the Year Ended:
	31-Dec-13	$	1,886		$	417		$	3,545		$	272		$	4,206		$	3,026		$	1,082		$	14,434
	Charge-offs	(212		)	—			—			(41		)	(677		)	(91		)				(1,021		)
	Recoveries	86			—			—			6			217			—						309
	Provision	340			(135		)	301			22			1,205			434			(319		)	1,848
	31-Dec-14	$	2,100		$	282		$	3,846		$	259		$	4,951		$	3,369		$	763		$	15,570
	31-Dec-12	$	2,344		$	601		$	3,050		$	304		$	4,536		$	3,405		$	1,058		$	15,298
	Charge-offs	(926		)	—			(11		)	(28		)	(431		)	(15		)	—			(1,411		)
	Recoveries	88			—			—			3			256			—			—			347
	Provision	380			(184		)	506			(7		)	(155		)	(364		)	24			200
	December 31, 2013	$	1,886		$	417		$	3,545		$	272		$	4,206		$	3,026		$	1,082		$	14,434
	31-Dec-11	$	1,927		$	602		$	3,136		$	350		$	4,496		$	3,414		$	1,078		$	15,003
	Charge-offs	(90		)	—			(206		)	(52		)	(401		)	(33		)	—			(782		)
	Recoveries	23			—			—			9			200			—			—			232
	Provision	484			(1		)	120			(3		)	241			24			(20		)	845
	31-Dec-12	$	2,344		$	601		$	3,050		$	304		$	4,536		$	3,405		$	1,058		$	15,298
	Allowance for Loan Losses
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Unallocated			Total
	31-Dec-14
	Allowance for loan losses - Loans Individually Evaluated for Impairment	$	—		$	—		$	—		$	—		$	—		$	109		$	—		$	109
	Allowance for loan losses - Loans Collectively Evaluated for Impairment	$	2,100		$	282		$	3,846		$	259		$	4,951		$	3,260		$	763		$	15,461
	Ending Loan Balance - Individually Evaluated for Impairment	$	494		$	—		$	1,492		$	—		$	118		$	2,237		$	—		$	4,341
	Ending Loan Balance - Collectively Evaluated for Impairment	$	99,017		$	18,815		$	319,805		$	7,665		$	429,258		$	534,367		$	—		$	1,408,927
	December 31, 2013
	Allowance for loan losses - Loans Individually Evaluated for Impairment	$	—		$	—		$	—		$	—		$	—		$	—		$	—		$	—
	Allowance for loan losses - Loans Collectively Evaluated for Impairment	$	1,886		$	417		$	3,545		$	272		$	4,206		$	3,026		$	1,082		$	14,434
	Ending Loan Balance - Individually Evaluated for Impairment	$	221		$	—		$	1,785		$	—		$	173		$	2,309		$	—		$	4,488
	Ending Loan Balance - Collectively Evaluated for Impairment	$	87,672		$	27,815		$	286,334		$	7,649		$	394,031		$	458,483		$	—		$	1,261,984
Financing Receivable Credit Quality Indicators [Table Text Block]	Loan Credit Quality Indicators
	The following table presents the credit quality indicators by loan category at December 31, 2014 and December 31, 2013:
	Loan Credit Quality Indicators
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
	December 31, 2014
	Credit Risk Profile by Creditworthiness Category:
	Satisfactory	$	85,949		$	18,815		$	298,932											$	403,696
	Special Mention	2,442			—			3,718												6,160
	Substandard	11,120			—			18,647												29,767
	Doubtful	—			—			—												—
	Credit Risk Profile Based on Payment Activity:
	Performing										$	7,661		$	428,965		$	532,127		968,753
	Nonperforming										4			411			4,477			4,892
	December 31, 2013
	Credit Risk Profile by Creditworthiness Category:
	Satisfactory	$	79,966		$	27,815		$	267,612											$	375,393
	Special Mention	204			—			634												838
	Substandard	7,723			—			19,873												27,596
	Doubtful	—			—			—												—
	Credit Risk Profile Based on Payment Activity:
	Performing										$	7,649		$	393,985		$	456,308		$	857,942
	Nonperforming										—			219			4,484			4,703
Impaired Financing Receivables [Table Text Block]	Impaired Loans
	The following table presents information on impaired loans based on whether the impaired loan has a recorded allowance or no recorded allowance:
	Impaired Loans
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
	December 31, 2014
	Recorded Investment:
	With No Related Allowance	$	494		$	—		$	1,492		$	—		$	118		$	1,678		$	3,782
	With a Related Allowance	—			—			—			—			—			559			559
	Unpaid Principal Balance:
	With No Related Allowance	$	494		$	—		$	1,492		$	—		$	118		$	1,678		$	3,782
	With a Related Allowance	—			—			—			—			—			559			559
	December 31, 2013
	Recorded Investment:
	With No Related Allowance	$	221		$	—		$	1,785		$	—		$	173		$	2,309		$	4,488
	With a Related Allowance	—			—			—			—			—			—			$	—
	Unpaid Principal Balance:
	With No Related Allowance	$	221		$	—		$	1,785		$	—		$	173		$	2,309		$	4,488
	With a Related Allowance	—			—			—			—			—			—			$	—
	For the Year-To-Date Period Ended:
	December 31, 2014
	Average Recorded Balance:
	With No Related Allowance	$	348		$	—		$	1,492		$	—		$	121		$	1,673		$	3,634
	With a Related Allowance	—			—			—			—			—			546			$	546
	Interest Income Recognized:
	With No Related Allowance	$	11		$	—		$	—		$	—		$	7		$	1		$	19
	With a Related Allowance	—			—			—			—			—			—			—
	Cash Basis Income:
	With No Related Allowance	$	—		$	—		$	—		$	—		$	—		$	—		$	—
	With a Related Allowance	—			—			—			—			—			—			—
	Related Allowance	—			—			—			—			—			109			$	109
	December 31, 2013
	Average Recorded Balance:
	With No Related Allowance	$	133		$	—		$	2,157		$	—		$	188		$	1,700		$	4,178
	With a Related Allowance	694			—			—			—			—			—			$	694
	Interest Income Recognized:
	With No Related Allowance	$	4		$	—		$	—		$	—		$	9		$	8		$	21
	With a Related Allowance	—			—			—			—			—			—			$	—
	Cash Basis Income:
	With No Related Allowance	$	—		$	—		$	—		$	—		$	—		$	—		$	—
	With a Related Allowance	—			—			—			—			—			—			$	—
	December 31, 2012
	Average Recorded Balance:
	With No Related Allowance	$	56		$	—		$	2,241		$	—		$	236		$	1,599		$	4,132
	With a Related Allowance	$	694		$	—		$	—		$	—		$	—		$	—		$	694
	Interest Income Recognized:
	With No Related Allowance	$	6		$	—		$	64		$	—		$	12		$	9		$	91
	With a Related Allowance	—			—			—			—			—			—			$	—
	Cash Basis Income:
	With No Related Allowance	$	—		$	—		$	64		$	—		$	—		$	—		$	64
	With a Related Allowance	$	—		$	—		$	—		$	—		$	—		$	—		$	—
Troubled Debt Restructurings on Financing Receivables [Table Text Block]	Loans Modified in Trouble Debt Restructurings
	The following table presents information on loans modified in trouble debt restructurings during the periods indicated:
	Loans Modified in Trouble Debt Restructurings During the Period
					Commercial			Commercial			Other
		Commercial			Construction			Real Estate			Consumer			Automobile			Residential			Total
	For the Year Ended:
	December 31, 2014
	Number of Loans	—			—			—			—			4			1			5
	Pre-Modification Outstanding Recorded Investment	$	—		$	—		$	—		$	—		$	36		$	574		$	610
	Post-Modification Outstanding Recorded Investment	$	—		$	—		$	—		$	—		$	36		$	574		$	610
	Subsequent Default, Number of Contracts	—			—			—			—			—			—			—
	Subsequent Default, Recorded Investment	—			—			—			—			—			—			—
	Commitments to lend additional funds to modified loans	—			—			—			—			—			—			—
	December 31, 2013
	Number of Loans	1			—			—			—			9			—			10
	Pre-Modification Outstanding Recorded Investment	$	169		$	—		$	—		$	—		$	88		$	—		$	257
	Post-Modification Outstanding Recorded Investment	$	200		$	—		$	—		$	—		$	88		$	—		$	288
	Subsequent Default, Number of Contracts	—			—			—			—			—			—			—
	Subsequent Default, Recorded Investment	—			—			—			—			—			—			—
	Commitments to lend additional funds to modified loans	—			—			—			—			—			—			—
	December 31, 2012
	Number of Loans	—			—			2			—			17			—			19
	Pre-Modification Outstanding Recorded Investment	$	—		$	—		$	47		$	—		$	160		$	—		$	207
	Post-Modification Outstanding Recorded Investment	$	—		$	—		$	47		$	—		$	160		$	—		$	207
	Subsequent Default, Number of Contracts	—			—			—			—			—			—			—
	Subsequent Default, Recorded Investment	—			—			—			—			—			—			—
	Commitments to lend additional funds to modified loans	—			—			—			—			—			—			—
Financing Receivable Supplemental Information [Table Text Block]	Schedule of Supplemental Loan Information
		2014			2013
	Supplemental Information:
	Unamortized deferred loan origination costs, net of deferred loan	$	2,771		$	2,152
	origination fees, included in the above balances
	Overdrawn deposit accounts, included in the above balances	973			501
	Pledged loans secured by one-to-four family residential mortgages	313,355			270,372
	under a blanket collateral agreement to secure borrowings from
	the Federal Home Loan Bank of New York
	Residential real estate loans serviced for Freddie Mac, not included	158,598			156,593
	in the balances above
	Loans held for sale at period-end, included in the above balances	398			64
	Loans to Related Parties:
	Balance at beginning of year	$	7,769		$	17,447
	Adjustment due to change in composition of related parties	—			(8,819		)
	New loans and renewals, during the year	694			2,253
	Repayments, during the year	(2,460		)	(3,112		)
	Balance at end of year	$	6,003		$	7,769

Premises_and_Equipment_Tables

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Table Text Block]	A summary of premises and equipment at December 31, 2014 and 2013 is presented below:
		2014			2013
	Land and Bank Premises	$	35,062		$	35,114
	Equipment, Furniture and Fixtures	22,003			20,851
	Leasehold Improvements	1,218			1,190
	Total Cost	58,283			57,155
	Accumulated Depreciation and Amortization	(29,795		)	(28,001		)
	Net Premises and Equipment	$	28,488		$	29,154
	Amounts charged to expense for depreciation totaled $2,238, $1,928 and $1,521 in 2014, 2013 and 2012, respectively.

Other_Intangible_Assets_Tables

Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets [Table Text Block]	The following table presents information on Arrow’s other intangible assets (other than goodwill) as of December 31, 2014, 2013 and 2012:
		Depositor			Mortgage			Customer Intangibles1			Total
		Intangibles1			Servicing
					Rights2
	Gross Carrying Amount, December 31, 2014	$	2,247		$	1,715		$	4,451		$	8,413
	Accumulated Amortization	(2,237		)	(883		)	(1,668		)	(4,788		)
	Net Carrying Amount, December 31, 2014	$	10		$	832		$	2,783		$	3,625
	Gross Carrying Amount, December 31, 2013	$	2,247		$	1,582		$	4,451		$	8,280
	Accumulated Amortization	(2,186		)	(622		)	(1,332		)	(4,140		)
	Net Carrying Amount, December 31, 2013	$	61		$	960		$	3,119		$	4,140
	Rollforward of Intangible Assets:
	Balance, December 31, 2011	$	286		$	599		$	3,864		$	4,749
	Intangible Assets Acquired	—			417			—			417
	Amortization of Intangible Assets	(133		)	(157		)	(384		)	(674		)
	Balance, December 31, 2012	153			859			3,480			4,492
	Intangible Assets Acquired	—			331			—			331
	Amortization of Intangible Assets	(92		)	(230		)	(361		)	(683		)
	Balance, December 31, 2013	61			960			3,119			4,140
	Intangible Assets Acquired	—			133			—			133
	Amortization of Intangible Assets	(51		)	(261		)	(336		)	(648		)
	Balance, December 31, 2014	$	10		$	832		$	2,783		$	3,625
	1 Amortization of depositor intangibles and customer intangibles are reported in the consolidated statements of income as a component of other operating expense.
	2 Amortization of mortgage servicing rights is reported in the consolidated statements of income as a reduction of mortgage servicing fee income, which is included with fees for other services to customers.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	The following table presents the remaining estimated annual amortization expense for Arrow's intangible assets as of December 31, 2014:
		Depositor			Mortgage			Customer Intangibles1			Total
		Intangibles1			Servicing
					Rights2
	Estimated Annual Amortization Expense:
	2015	$	10		$	252		$	319		$	581
	2016	—			232			301			533
	2017	—			172			281			453
	2018	—			118			263			381
	2019	—			45			245			290
	Later Years	—			13			1,374			1,387
	Total	$	10		$	832		$	2,783		$	3,625
	1 Amortization of depositor intangibles and customer intangibles are reported in the consolidated statements of income as a component of other operating expense.
	2 Amortization of mortgage servicing rights is reported in the consolidated statements of income as a reduction of mortgage servicing fee income, which is included with fees for other services to customers.

Guarantees_Tables

Guarantees (Tables)	12 Months Ended
	Dec. 31, 2014
Guarantees [Abstract]
Schedule of Guarantor Obligations [Table Text Block]	The following table presents the notional amount and fair value of Arrow's off-balance sheet commitments to extend credit and commitments under standby letters of credit as of December 31, 2014 and 2013:
	Balance at December 31,	2014		2013
	Notional Amount:
	Commitments to Extend Credit	$	249,803	$	237,940
	Standby Letters of Credit	3,317		3,345
	Fair Value:
	Commitments to Extend Credit	$	—	$	—
	Standby Letters of Credit	39		65

Time_Deposits_Tables

Time Deposits (Tables)	12 Months Ended
	Dec. 31, 2014
Time Deposits [Abstract]
Maturities of Time Deposits [Table Text Block]	The following summarizes the contractual maturities of time deposits during years subsequent to December 31, 2014:
	Year of Maturity	Total Time
		Deposits
	2015	$	124,406
	2016	28,487
	2017	19,869
	2018	11,845
	2019	17,126
	2020 and Beyond	4,110
	Total	$	205,843

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of Short-term Debt [Table Text Block]	Schedule of Short-Term Borrowings:
		2014			2013
	Balances at December 31:
	Overnight Advances from the Federal Home Loan Bank of New York	$	41,000		$	53,000
	Securities Sold Under Agreements to Repurchase	19,421			11,777
	Total Short-Term Borrowings	$	60,421		$	64,777
	Maximum Borrowing Capacity at December 31:
	Federal Funds Purchased	$	35,000		$	30,000
	Overnight Advances from the Federal Home Loan Bank of New York	203,885			214,000
	Federal Reserve Bank of New York	307,159			302,000
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturity Schedule of FHBLNY Term Advances:
			Balances					Weighted Average Rate
	Final Maturity		2014			2013		2014		2013
	First Year		$	10,000		$	10,000	3.88	%	1.43	%
	Second Year		—			10,000		—	%	3.88	%
	Third Year		—			—		—	%	—	%
	Total		$	10,000		$	20,000	3.88	%	2.66	%
Schedule of Long-term Debt Instruments [Table Text Block]	Schedule of Guaranteed Preferred Beneficial Interests in Corporation's Junior Subordinated Debentures
		2014			2013
	ACST II
	Balance at December 31,	$	10,000		$	10,000
	Period-End Interest Rate	3.38		%	3.4		%
	ACST III
	Balance at December 31,	$	10,000		$	10,000
	Period-End Interest Rate	2.23		%	2.25		%

Comprehensive_Income_Tables

Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2014
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Comprehensive Income (Loss) [Table Text Block]	The following table presents the components of other comprehensive income for the years ended December 31, 2014, 2013 and 2012:
	Schedule of Comprehensive Income
		Before-Tax				Tax			Net-of-Tax
		Amount				(Expense)			Amount
						Benefit
	2014
	Net Unrealized Securities Holding Gains Arising During the Period	$	356			$	(124	)	$	232
	Reclassification Adjustment for Securities Gains Included in Net Income	(110		)		43			(67		)
	Net Retirement Plan Loss	(4,610		)		1,764			(2,846		)
	Net Retirement Plan Prior Service Credit	(570		)		223			(347		)
	Amortization of Net Retirement Plan Actuarial Loss	474				(186		)	288
	Accretion of Net Retirement Plan Prior Service Credit	(87		)		34			(53		)
	Other Comprehensive Income	$	(4,547	)		$	1,754		$	(2,793	)
	2013
	Net Unrealized Securities Holding Gains Arising During the Period	$	(4,843	)		$	1,918		$	(2,925	)
	Reclassification Adjustment for Securities Gains Included in Net Income	(540		)		214			(326		)
	Net Retirement Plan Gain	10,640				(4,215		)	6,425
	Amortization of Net Retirement Plan Actuarial Loss	1,513				(599		)	914
	Accretion of Net Retirement Plan Prior Service Credit	2				(1		)	1
	Other Comprehensive Income	$	6,772			$	(2,683	)	$	4,089
	2012
	Net Unrealized Securities Holding Gains Arising During the Period	$	(1,094	)		$	433		$	(661	)
	Reclassification Adjustment for Securities Gains Included in Net Income	(865		)		343			(522		)
	Net Retirement Plan Loss	(2,218		)		878			(1,340		)
	Net Retirement Plan Prior Service Credit	(405		)		160			(245		)
	Amortization of Net Retirement Plan Actuarial Loss	1,677				(664		)	1,013
	Accretion of Net Retirement Plan Prior Service Credit	(20		)		8			(12		)
	Other Comprehensive Income	$	(2,925	)		$	1,158		$	(1,767	)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents the changes in accumulated other comprehensive income by component:
	Changes in Accumulated Other Comprehensive Income (Loss) by Component (1)
		Unrealized				Defined Benefit Plan Items
		Gains and
		Losses on							Net Prior
		Available-for-				Net Gain			Service
		Sale Securities				(Loss)			(Cost ) Credit			Total
	For the Year-To-Date periods ended:
	31-Dec-13	$	2,374			$	(6,697	)	$	(50	)	$	(4,373	)
	Other comprehensive income (loss) before reclassifications	232				(2,846		)	(347		)	(2,961		)
	Amounts reclassified from accumulated other comprehensive income (loss)	(67		)		288			(53		)	168
	Net current-period other comprehensive income	165				(2,558		)	(400		)	(2,793		)
	December 31, 2014	$	2,539			$	(9,255	)	$	(450	)	$	(7,166	)
	December 31, 2012	$	5,625			$	(14,036	)	$	(51	)	$	(8,462	)
	Other comprehensive income (loss) before reclassifications	(2,925		)		6,425			—			3,500
	Amounts reclassified from accumulated other comprehensive income (loss)	(326		)		914			1			589
	Net current-period other comprehensive income	(3,251		)		7,339			1			4,089
	December 31, 2013	$	2,374			$	(6,697	)	$	(50	)	$	(4,373	)
	December 31, 2011	$	6,808			$	(13,709	)	$	206		$	(6,695	)
	Other comprehensive income (loss) before reclassifications	(661		)		(1,340		)	(245		)	(2,246		)
	Amounts reclassified from accumulated other comprehensive income (loss)	(522		)		1,013			(12		)	479
	Net current-period other comprehensive income	(1,183		)		(327		)	(257		)	(1,767		)
	December 31, 2012	$	5,625			$	(14,036	)	$	(51	)	$	(8,462	)
	(1) All amounts are net of tax. Amounts in parentheses indicate debits.
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following table presents the reclassifications out of accumulated other comprehensive income:
	Reclassifications Out of Accumulated Other Comprehensive Income (1)
			Amounts Reclassified
	Details about Accumulated Other		from Accumulated Other				Affected Line Item in the Statement
	Comprehensive Income Components		Comprehensive Income				Where Net Income Is Presented
	For the Year-to-date periods ended:
	December 31, 2014
	Unrealized gains and losses on available-for-sale securities
			$	110			Gain on Securities Transactions, Net
			110				Total before tax
			(43		)		Provision for Income Taxes
			$	67			Net of tax
	Amortization of defined benefit pension items
	Prior-service costs		$	87		(2)	Salaries and Employee Benefits
	Actuarial gains/(losses)		(474		)	(2)	Salaries and Employee Benefits
			(387		)		Total before tax
			152				Provision for Income Taxes
			$	(235	)		Net of tax
	Total reclassifications for the period		$	(168	)		Net of tax
	December 31, 2013
	Unrealized gains and losses on available-for-sale securities
			$	540			Gain on Securities Transactions, Net
			540				Total before tax
			(214		)		Provision for Income Taxes
			$	326			Net of tax
	Amortization of defined benefit pension items
	Prior-service costs		(2		)	(2)	Salaries and Employee Benefits
	Actuarial gains/(losses)		$	(1,513	)	(2)	Salaries and Employee Benefits
			(1,515		)		Total before tax
			600				Provision for Income Taxes
			$	(915	)		Net of tax
	Total reclassifications for the period		$	(589	)		Net of tax
	Reclassifications Out of Accumulated Other Comprehensive Income (1)
			Amounts Reclassified
	Details about Accumulated Other		from Accumulated Other				Affected Line Item in the Statement
	Comprehensive Income Components		Comprehensive Income				Where Net Income Is Presented
	December 31, 2012
	Unrealized gains and losses on available-for-sale securities
			$	865			Gain on Securities Transactions, Net
			865				Total before tax
			(343		)		Provision for Income Taxes
			$	522			Net of tax
	Amortization of defined benefit pension items
	Prior-service costs		20			(2)	Salaries and Employee Benefits
	Actuarial gains/(losses)		$	(1,677	)	(2)	Salaries and Employee Benefits
			(1,657		)		Total before tax
			656				Provision for Income Taxes
			$	(1,001	)		Net of tax
	Total reclassifications for the period		$	(479	)		Net of tax
	(1) Amounts in parentheses indicate debits to profit/loss.
	(2) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see pension footnote for additional details).

Stock_Based_Compensation_Table

Stock Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	Roll Forward Schedule of Stock Option Plan by Shares and Weighted Average Exercise Prices
		Stock Option Plans
	Roll Forward of Shares Outstanding:
	Outstanding at January 1, 2014	397,177
	Granted	75,518
	Exercised	(62,269		)
	Forfeited	(8,984		)
	Outstanding at December 31, 2014	401,442
	Exercisable at December 31, 2014	266,654
	Vested and Expected to Vest	134,788
	Roll Forward of Shares Outstanding - Weighted Average Exercise Price:
	Outstanding at January 1, 2014	$	22.44
	Granted	24.51
	Exercised	23.35
	Forfeited	23.89
	Outstanding at December 31, 2014	22.66
	Exercisable at December 31, 2014	21.74
	Vested and Expected to Vest	24.47
	Weighted Average Remaining Contractual Life (in years):
	Outstanding at December 31, 2014	5.83
	Exercisable at December 31, 2014	4.67
	Vested and Expected to Vest	8.13
	Aggregate Intrinsic Value:
	Outstanding at December 31, 2014	$	1,939
	Exercisable at December 31, 2014	1,533
	Vested and Expected to Vest	406
	Shares Available for Grant at Period-End	445,000
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Schedule of Shares Authorized Under the Stock Option Plan by Exercise Price Range
		Exercise Price Ranges
		$18.71 to $19.48			$20.82			$21.83		$23.30 to $23.95			$24.51 to $25.27		Total
	Outstanding Options at
	31-Dec-14
	Number of Shares Outstanding	72,516			27,470			64,829		153,236			83,391		401,442
	Weighted-Average Remaining Contractual Life (in years)	3.69			1.92			5.08		6.66			8.05		5.83
	Weighted-Average Exercise Price	$	19.24		$	20.82		$	21.83	$	23.61		$	24.6	$	22.55
	Exercisable Options at
	31-Dec-14
	Number of Shares Outstanding	72,516			27,470			64,829		92,333			9,506		266,654
	Weighted-Average Remaining Contractual Life (in years)	3.69			1.92			5.08		6.44			8.05		4.67
	Weighted-Average Exercise Price	$	19.24		$	20.82		$	21.83	$	23.56		$	25.27	$	21.74
Other Stock Based Compensation Disclosure Table [Table Text Block]	Schedule of Other Stock Option Plan Information
			2014				2013			2012
	Shares Granted		75,518				10,404			78,848
	Weighted Average Grant Date Information:
	Fair Value of Options Granted		$	5.92			$	5.35		$	5.77
	Fair Value Assumptions:
	Dividend Yield		3.97		%		4.2		%	3.93		%
	Expected Volatility		35.3		%		36.57		%	37.43		%
	Risk Free Interest Rate		2.19		%		1.31		%	1.22		%
	Expected Lives (in years)		6.85				6.71			6.46
	Amount Expensed During the Year		$	360			$	372		$	424
	Compensation Costs for Non-vested Awards Not Yet Recognized		478				420			737
	Weighted Average Expected Vesting Period, In Years		1.68				1.45			1.71
	Proceeds From Stock Options Exercised		$	1,454			$	1,254		$	2,105
	Tax Benefits Related to Stock Options Exercised		25				23			68
	Intrinsic Value of Stock Options Exercised		170				267			2,434
Schedule of Employee Stock Ownership Plan (ESOP) Disclosures [Table Text Block]	Schedule of ESOP Compensation Expense
			2014				2013			2012
	ESOP Compensation Expense		$	800			$	600		$	550
	As the debt is repaid, shares are released from collateral based on the proportion of debt paid to total debt outstanding for the year and allocated to active employees.
	Shares pledged as collateral are reported as unallocated ESOP shares in stockholders’ equity.  As shares are released from collateral, Arrow reports compensation expense equal to the current average market price of the shares, and the shares become outstanding for earnings per share computations.  The ESOP shares as of December 31, 2014 were as follows:
	Schedule of Shares in ESOP Plan
	ESOP Plan Shares:	2014
	Allocated Shares	690,853
	Shares Released for Allocation During 2013	17,300
	Unallocated Shares	71,748
	Total ESOP Shares	779,901
	Market Value of Unallocated Shares	$	1,972

Retirement_Benefit_Plans_Table

Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Schedule of Defined Benefit Plans Disclosures [Table Text Block]	The following tables set forth changes in the plans’ benefit obligations (projected benefit obligation for pension benefits and accumulated benefit obligation for postretirement benefits) and changes in the plans’ assets and the funded status of the pension plans and other postretirement benefit plan at December 31:
	Schedule of Defined Benefit Plan Disclosures
		Employees'			Select			Postretirement
		Pension			Executive			Benefit
		Plan			Retirement			Plans
					Plan
	Defined Benefit Plan Funded Status
	31-Dec-14
	Fair Value of Plan Assets	$	45,704		$	—		$	—
	Benefit Obligation	36,966			5,072			9,170
	Funded Status of Plan	$	8,738		$	(5,072	)	$	(9,170	)
	31-Dec-13
	Fair Value of Plan Assets	$	44,653		$	—		$	—
	Benefit Obligation	33,259			4,459			7,619
	Funded Status of Plan	$	11,394		$	(4,459	)	$	(7,619	)
	Change in Benefit Obligation
	Benefit Obligation, at January 1, 2014	$	33,259		$	4,459		$	7,619
	Service Cost	1,410			10			173
	Interest Cost	1,621			206			374
	Plan Participants' Contributions	—			—			383
	Amendments	—			—			570
	Actuarial Gain	2,909			870			884
	Benefits Paid	(2,233		)	(473		)	(833		)
	Benefit Obligation, at December 31, 2014	$	36,966		$	5,072		$	9,170
	Schedule of Defined Benefit Plan Disclosures
		Employees'			Select			Postretirement
		Pension			Executive			Benefit
		Plan			Retirement			Plans
					Plan
	Benefit Obligation, at January 1, 2013	$	37,046		$	5,324		$	9,213
	Service Cost	1,506			—			211
	Interest Cost	1,261			163			308
	Plan Participants' Contributions	—			—			368
	Amendments	—			—			—
	Actuarial Loss	(3,820		)	(555		)	(1,648		)
	Benefits Paid	(2,734		)	(473		)	(833		)
	Benefit Obligation, at December 31, 2013	$	33,259		$	4,459		$	7,619
	Change in Fair Value of Plan Assets
	Fair Value of Plan Assets, at January 1, 2014	$	44,653		$	—		$	—
	Actual Return on Plan Assets	3,284			—			—
	Employer Contributions	—			473			450
	Plan Participants' Contributions	—			—			383
	Benefits Paid	(2,233		)	(473		)	(833		)
	Fair Value of Plan Assets, at December 31, 2014	$	45,704		$	—		$	—
	Change in Fair Value of Plan Assets, continued
	Fair Value of Plan Assets, at January 1, 2013	$	39,880		$	—		$	—
	Actual Return on Plan Assets	7,507			—			—
	Employer Contributions	—			473			465
	Plan Participants' Contributions	—			—			368
	Benefits Paid	(2,734		)	(473		)	(833		)
	Fair Value of Plan Assets, at December 31, 2013	$	44,653		$	—		$	—
	Accumulated Benefit Obligation at December 31, 2014	$	36,530		$	5,072		$	9,170
	Amounts Recognized in the Consolidated Balance Sheets
	31-Dec-14
	Prepaid Pension Asset	$	8,738		$	—		—
	Accrued Benefit Liability	—			(5,072		)	(9,170		)
	Net Benefit Recognized	$	8,738		$	(5,072	)	$	(9,170	)
	31-Dec-13
	Prepaid Pension Asset	$	11,394		$	—		—
	Accrued Benefit Liability	—			(4,459		)	(7,619		)
	Net Benefit Recognized	$	11,394		$	(4,459	)	$	(7,619	)
	Amounts Recognized in Other Comprehensive Income (Loss)
	For the Year Ended December 31, 2014
	Net Unamortized Gain Arising During the Period	$	2,855		$	871		$	884
Net Prior Service Cost Arising During the Period	—			—			570
Amortization of Net Loss	(356		)	(93		)	(25		)
Amortization of Prior Service (Cost) Credit	45			(72		)	114
Total Other Comprehensive (Loss) Income for Pension and	$	2,544		$	706		$	1,543
Other Postretirement Benefit Plans
For the Year Ended December 31, 2013
Net Unamortized Loss Arising During the Period	$	(8,438	)	$	(554	)	$	(1,648	)
Net Prior Service Cost Arising During the Period	—			—			—
Amortization of Net Loss	(1,231		)	(140		)	(142		)
Amortization of Prior Service (Cost) Credit	(37		)	(79		)	114
Total Other Comprehensive (Loss) Income for Pension and	$	(9,706	)	$	(773	)	$	(1,676	)
Other Postretirement Benefit Plans
Schedule of Defined Benefit Plan Disclosures
	Employees'			Select			Postretirement
	Pension			Executive			Benefit
	Plan			Retirement			Plans
				Plan
For the Year Ended December 31, 2012
Net Unamortized Loss Arising During the Period	$	1,286		$	441		$	491
Net Prior Service Cost Arising During the Period	—			405			—
Amortization of Net Loss	(1,387		)	(156		)	(134		)
Amortization of Prior Service (Cost) Credit	(41		)	(53		)	114
Total Other Comprehensive (Loss) Income for Pension and	$	(142	)	$	637		$	471
Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income
31-Dec-14
Net Actuarial Loss	$	10,856		$	2,452		$	1,919
Prior Service (Credit) Cost	(210		)	570			379
Total Accumulated Other Comprehensive Income, Before Tax	$	10,646		$	3,022		$	2,298
31-Dec-13
Net Actuarial Loss	$	8,357		$	1,674		$	1,060
Prior Service (Credit) Cost	(255		)	642			(305		)
Total Accumulated Other Comprehensive Income, Before Tax	$	8,102		$	2,316		$	755
Amounts that will be Amortized from Accumulated
Other Comprehensive Income the Next Year
Net Actuarial Loss	$	556		$	121		$	95
Prior Service (Credit) Cost	$	(83	)	$	58		$	(31	)
Net Periodic Benefit Cost
For the Year Ended December 31, 2014
Service Cost	$	1,410		$	10		$	173
Interest Cost	1,621			206			374
Expected Return on Plan Assets	(3,230		)	—			—
Amortization of Prior Service (Credit) Cost	(45		)	72			(114		)
Amortization of Net Loss	356			93			25
Net Periodic Benefit Cost	$	112		$	381		$	458
For the Year Ended December 31, 2013
Service Cost	$	1,506		$	—		$	211
Interest Cost	1,261			163			308
Expected Return on Plan Assets	(2,889		)	—			—
Amortization of Prior Service (Credit) Cost	37			79			(114		)
Amortization of Net Loss	1,232			139			142
Net Periodic Benefit Cost	$	1,147		$	381		$	547
For the Year Ended December 31, 2012
Service Cost	$	1,467		$	87		$	202
Interest Cost	1,436			190			338
Expected Return on Plan Assets	(2,865		)	—			—
Amortization of Prior Service (Credit) Cost	41			53			(114		)
Amortization of Net Loss	1,387			156			134
Net Periodic Benefit Cost	$	1,466		$	486		$	560
Weighted-Average Assumptions Used in
Calculating Benefit Obligation
31-Dec-14
Discount Rate	4.31		%	4.26		%	4.31		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Schedule of Defined Benefit Plan Disclosures
	Employees'			Select			Postretirement
	Pension			Executive			Benefit
	Plan			Retirement			Plans
				Plan
Interest Rate Credit for Determining	3.04		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	4.75		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	4.75		%	4.75		%
Equivalent Lump Sum Amounts
31-Dec-13
Discount Rate	5.1		%	4.85		%	5.1		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	4		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	5.25		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	5.25		%	5.25		%
Equivalent Lump Sum Amounts
Weighted-Average Assumptions Used in
Calculating Net Periodic Benefit Cost
31-Dec-14
Discount Rate	5.1		%	4.85		%	5.1		%
Expected Long-Term Return on Plan Assets	7.5		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	4		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	5.25		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	5.25		%	5.25		%
Equivalent Lump Sum Amounts
31-Dec-13
Discount Rate	3.55		%	3.15		%	3.55		%
Expected Long-Term Return on Plan Assets	7.5		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	3		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	4.5		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	4.5		%	4.5		%
Equivalent Lump Sum Amounts
31-Dec-12
Discount Rate	4.05		%	4.05		%	4.05		%
Expected Long-Term Return on Plan Assets	7.5		%
Rate of Compensation Increase	3.5		%	3.5		%	3.5		%
Interest Rate Credit for Determining	3.25		%
Projected Cash Balance Account
Interest Rate to Annuitize Cash	5		%
Balance Account
Interest Rate to Convert Annuities to Actuarially	5		%	5		%
Equivalent Lump Sum Amounts
Schedule of Defined Benefit Plan Disclosures
Information about Defined Benefit Plan Assets - Employees' Pension Plan
Fair Value Measurements Using:
Asset Category	Quoted Prices			Significant Other Observable Inputs			Significant Unobservable Inputs			Total		Percent of Total		Target Allocation Minimum		Target Allocation Maximum
	in Active Markets			(Level 2)			(Level 3)
	for Identical Assets
	(Level 1)
December 31, 2014
Cash	$	20		$	—		$	—		$	20	—	%	—	%	15	%
Interest-Bearing Money Market Fund	4,322			—			—			4,322		9.5	%	—	%	15	%
Arrow Common Stock1	4,551			—			—			4,551		10	%	—	%	10	%
North Country Funds - Equity 2	18,975			—			—			18,975		41.4	%
Other Mutual Funds - Equity	10,954			—			—			10,954		24	%
Total Equity Funds	29,929			—			—			29,929		65.4	%	66	%	85	%
North Country Funds - Fixed income 2	5,436			—			—			5,436		11.9	%
Other Mutual Funds - Fixed Income	1,446			—			—			1,446		3.2	%
Total Fixed Income Funds	6,882			—			—			6,882		15.1	%	15	%	30	%
Total	$	45,704		$	—		$	—		$	45,704	100	%
December 31, 2013
Cash	$	7		$	—		$	—		$	7	—	%	—	%	15	%
Interest-Bearing Money Market Fund	3,941			—			—			3,941		8.8	%	—	%	15	%
Arrow Common Stock1	4,291			—			—			4,291		9.6	%	—	%	10	%
North Country Funds - Equity 2	17,419			—			—			17,419		39.1	%
Other Mutual Funds - Equity	14,338			—			—			14,338		32.1	%
Total Equity Funds	31,757			—			—			31,757		71.2	%	55	%	85	%
North Country Funds - Fixed income 2	4,309			—			—			4,309		9.6	%
Other Mutual Funds - Fixed Income	348			—			—			348		0.8	%
Total Fixed Income Funds	4,657			—			—			4,657		10.4	%	10	%	30	%
Total	$	44,653		$	—		$	—		$	44,653	100	%

Other_Expenses_Tables

Other Expenses (Tables)	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Other Income and Other Expense Disclosure [Text Block]	Other operating expenses included in the consolidated statements of income are as follows:
		2014		2013		2012
	Computer Services	$	3,659	$	3,261	$	2,263
	Legal and Other Professional Fees	1,836		1,823		1,962
	Postage and Courier	1,084		1,046		1,040
	Stationery and Printing	851		905		975
	Advertising and Promotion	886		879		831
	Telephone and Communications	746		804		808
	Intangible Asset Amortization	387		452		518
	All Other	3,531		3,486		3,243
	Total Other Operating Expense	$	12,980	$	12,656	$	11,640

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	The provision for income taxes is summarized below:
	Current Tax Expense:	2014			2013			2012
	Federal	$	9,270		$	7,933		$	8,763
	State	1,203			852			1,251
	Total Current Tax Expense	10,473			8,785			10,014
	Deferred Tax Expense (Benefit):
	Federal	(315		)	172			(290		)
	State	16			122			(63		)
	Total Deferred Tax Expense (Benefit)	(299		)	294			(353		)
	Total Provision for Income Taxes	$	10,174		$	9,079		$	9,661
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The provisions for income taxes differed from the amounts computed by applying the U.S. Federal Income Tax Rate of 35% for 2014, 2013 and 2012 to pre-tax income as a result of the following:
		2014			2013			2012
	Computed Tax Expense at Statutory Rate	$	11,737		$	10,806		$	11,144
	Increase (Decrease) in Income Taxes Resulting From:
	Tax-Exempt Income	(2,215		)	(2,238		)	(2,132		)
	Nondeductible Interest Expense	51			80			95
	State Taxes, Net of Federal Income Tax Benefit	791			633			814
	Other Items, Net	(190		)	(202		)	(260		)
	Total Provision for Income Taxes	$	10,174		$	9,079		$	9,661
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2014 and 2013 are presented below:
		2014			2013
	Deferred Tax Assets:
	Allowance for Loan Losses	$	6,113		$	5,794
	Pension and Deferred Compensation Plans	3,885			3,999
	Pension Liability Included in Accumulated Other Comprehensive Income	6,263			4,426
	Other	614			566
	Total Gross Deferred Tax Assets	16,875			14,785
	Valuation Allowance for Deferred Tax Assets	—			—
	Total Gross Deferred Tax Assets, Net of Valuation Allowance	$	16,875		$	14,785
	Deferred Tax Liabilities:
	Pension Plans	$	7,604		$	7,724
	Depreciation	1,222			1,561
	Deferred Income	3,927			3,526
	Net Unrealized Gains on Securities Available-for-Sale Included in	1,638			1,557
	Accumulated Other Comprehensive Income
	Goodwill	5,242			5,230
	Total Gross Deferred Tax Liabilities	$	19,633		$	19,598

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table presents a reconciliation of the numerator and denominator used in the calculation of basic and diluted earnings per common share ("EPS") for each of the years in the three-year period ended December 31, 2014.  All share and per share amounts have been adjusted for the 2014 2% stock dividend.
	Earnings Per Share
		Year-to-Date Period Ended:
		12/31/14		12/31/13		12/31/12
	Earnings Per Share - Basic:
	Net Income	$	23,360	$	21,795	$	22,179
	Weighted Average Shares - Basic	12,604		12,542		12,492
	Earnings Per Share - Basic	$	1.85	$	1.74	$	1.78
	Earnings Per Share - Diluted:
	Net Income	$	23,360	$	21,795	$	22,179
	Weighted Average Shares - Basic	12,604		12,542		12,492
	Dilutive Average Shares Attributable to Stock Options	29		31		10
	Weighted Average Shares - Diluted	12,633		12,573		12,502
	Earnings Per Share - Diluted	$	1.85	$	1.73	$	1.77
	Antidilutive Shares Excluded from the Calculation	—		47		203
	of Earnings Per Share

Fair_Values_Tables

Fair Values (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]	The table below presents the financial instrument's fair value and the amounts within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement:
	Fair Value of Assets and Liabilities Measured on a Recurring and Nonrecurring Basis
		Fair Value Measurements at Reporting Date Using:
	Fair Value of Assets and Liabilities Measured on a Recurring Basis:	Fair Value		Quoted Prices		Significant Other		Significant Unobservable Inputs		Total Gains (Losses)
				In Active Markets for Identical Assets		Observable Inputs		(Level 3)
				(Level 1)		(Level 2)
	December 31, 2014
	Securities Available-for Sale:
	U.S. Agency Obligations	$	137,603	$	—	$	137,603	$	—
	State and Municipal Obligations	81,730		—		81,730		—
	Mortgage-Backed Securities - Residential	128,827		—		128,827		—
	Corporate and Other Debt Securities	16,725		—		16,725		—
	Mutual Funds and Equity Securities	1,254		—		1,254		—
	Total Securities Available-for-Sale	$	366,139	$	—	$	366,139	$	—
	December 31, 2013
	Securities Available-for Sale:
	U.S. Agency Obligations	$	136,475	$	—	$	136,475	$	—
	State and Municipal Obligations	127,389		—		127,389		—
	Mortgage-Backed Securities - Residential	175,778		—		175,778		—
	Corporate and Other Debt Securities	16,798		—		16,798		—
	Mutual Funds and Equity Securities	1,166		—		1,166		—
	Total Securities Available-for Sale	$	457,606	$	—	$	457,606	$	—
	Fair Value of Assets and Liabilities Measured on a Nonrecurring Basis:
	December 31, 2014
	Collateral Dependent Impaired Loans	$	574	$	—	$	—	$	574	$	(109	)
	Other Real Estate Owned and Repossessed Assets, Net	$	393	$	—	$	—	$	393	$	(15	)
	December 31, 2013
	Other Real Estate Owned and Repossessed Assets, Net	$	144	$	—	$	—	$	144	$	(79	)
Fair Value, by Balance Sheet Grouping [Table Text Block]	Fair Value by Balance Sheet Grouping
	The following table presents a summary of the carrying amount, the fair value or an amount approximating fair value and the fair value hierarchy of Arrow’s financial instruments:
	Schedule of Fair Values by Balance Sheet Grouping
						Fair Value Hierarchy
		Carrying		Fair		Level 1		Level 2		Level 3
		Amount		Value
	December 31, 2014
	Cash and Cash Equivalents	$	46,295	$	46,295	$	46,295	$	—	$	—
	Securities Available-for-Sale	366,139		366,139		—		366,139		—
	Securities Held-to-Maturity	302,024		308,566		—		308,566		—
	Federal Home Loan Bank and Federal Reserve Bank Stock	4,851		4,851		4,851		—		—
	Net Loans	1,397,698		1,405,454		—		—		1,405,454
	Accrued Interest Receivable	5,834		5,834		5,834		—		—
	Deposits	1,902,948		1,899,682		1,697,105		202,577		—
	Federal Funds Purchased and Securities Sold Under Agreements to Repurchase	19,421		19,421		19,421		—		—
	Federal Home Loan Bank Term Advances	51,000		51,258		41,000		10,258		—
	Junior Subordinated Obligations Issued	20,000		20,000		—		20,000		—
	to Unconsolidated Subsidiary Trusts
	Accrued Interest Payable	274		274		274		—		—
	December 31, 2013
	Cash and Cash Equivalents	$	49,980	$	49,980	$	49,980	$	—	$	—
	Securities Available-for-Sale	457,606		457,606		—		457,606		—
	Securities Held-to-Maturity	299,261		302,305		—		302,305		—
	Federal Home Loan Bank and Federal Reserve Bank Stock	6,281		6,281		6,281		—		—
	Net Loans	1,252,038		1,266,020		—		—		1,266,020
	Accrued Interest Receivable	5,745		5,745		5,745		—		—
	Deposits	1,842,330		1,839,613		1,595,103		244,510		—
	Federal Funds Purchased and Securities Sold Under Agreements to Repurchase	11,777		11,777		11,777		—		—
	Federal Home Loan Bank Term Advances	73,000		74,629		53,000		21,629		—
	Junior Subordinated Obligations Issued	20,000		20,000		—		20,000		—
	to Unconsolidated Subsidiary Trusts
	Accrued Interest Payable	439		439		439		—		—

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Schedule of Rent Expense [Table Text Block]	ental expense for the years ended December 31, 2014, 2013 and 2012 was as follows:
		2014		2013		2012
	Net Rental Expense	$	784	$	671	$	597
Schedule of Future Minimum Rental Payments for Operationg Leases [Table Text Block]	Future minimum lease payments on operating leases at December 31, 2014 were as follows:
		Operating
		Leases
	2015	$	686
	2016	483
	2017	389
	2018	318
	2019	266
	Later Years	372
	Total Minimum Lease Payments	$	2,514

Regulatory_Matters_Tables

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2014
Banking and Thrift [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]	Arrow’s and its subsidiary banks’, Glens Falls National Bank and Trust Company (“Glens Falls National”) and Saratoga National Bank and Trust Company (“Saratoga National”), actual capital amounts and ratios are presented in the table below as of December 31, 2014 and 2013:
		Actual				Minimum Amounts For Capital Adequacy Purposes						Minimum Amounts To Be Well-Capitalized
		Amount		Ratio		Amount			Ratio			Amount				Ratio
	As of December 31, 2014:
	Total Capital
	(to Risk Weighted Assets):
	Arrow	$	225,766	15.5	%	$	116,524		8	%		$	145,655			10	%
	Glens Falls National	183,446		15.5	%	94,682			8	%		118,352				10	%
	Saratoga National	35,217		13.3	%	21,183			8	%		26,479				10	%
	Tier I Capital
	(to Risk Weighted Assets):
	Arrow	210,136		14.5	%	57,969			4	%		86,953				6	%
	Glens Falls National	170,497		14.4	%	47,360			4	%		71,040				6	%
	Saratoga National	32,596		12.3	%	10,600			4	%		15,900				6	%
	Tier I Capital
	(to Average Assets):
	Arrow	210,136		9.4	%	89,420			4	%		89,420				4	%
	Glens Falls National	170,497		9.1	%	74,944			4	%		93,680				5	%
	Saratoga National	32,596		9.4	%	13,871			4	%		17,338				5	%
		Actual				Minimum Amounts For Capital					Minimum Amounts To Be Well-Capitalized
						Adequacy Purposes
		Amount		Ratio		Amount		Ratio			Amount			Ratio
	As of December 31, 2013:
	Total Capital
	(to Risk Weighted Assets):
	Arrow	$	212,360	15.8	%	107,524		8	%		134,405			10	%
	Glens Falls National	172,720		15.4	%	89,725		8	%		112,156			10	%
	Saratoga National	33,396		14.8	%	18,052		8	%		22,565			10	%
	Tier I Capital
	(to Risk Weighted Assets):
	Arrow	197,906		14.7	%	53,852		4	%		80,778			6	%
	Glens Falls National	160,849		14.4	%	44,680		4	%		67,020			6	%
	Saratoga National	30,833		13.7	%	9,002		4	%		13,504			6	%
	Tier I Capital
	(to Average Assets):
	Arrow	197,906		9.2	%	86,046		4	%		86,046			4	%
	Glens Falls National	160,849		8.8	%	73,113		4	%		91,391			5	%
	Saratoga National	30,833		9.7	%	12,715		4	%		15,893			5	%

Parent_Only_Financial_Informat1

Parent Only Financial Information (Tables)	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of Condensed Financial Statements [Table Text Block]	Condensed financial information for Arrow Financial Corporation is as follows:
	BALANCE SHEETS	December 31,
	ASSETS	2014			2013
	Interest-Bearing Deposits with Subsidiary Banks	$	3,013		$	3,349
	Available-for-Sale Securities	1,254			1,166
	Held-to-Maturity Securities	1,000			1,000
	Investment in Subsidiaries at Equity	214,813			206,680
	Other Assets	6,538			5,807
	Total Assets	$	226,618		$	218,002
	LIABILITIES
	Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	$	20,000		$	20,000
	Other Liabilities	5,692			5,848
	Total Liabilities	25,692			25,848
	STOCKHOLDERS’ EQUITY
	Total Stockholders’ Equity	200,926			192,154
	Total Liabilities and Stockholders’ Equity	$	226,618		$	218,002
	STATEMENTS OF INCOME	Years Ended December 31,
	Income:	2014			2013			2012
	Dividends from Bank Subsidiaries	$	13,300		$	12,900		$	12,700
	Interest and Dividends on Investments	116			116			123
	Other Income (Including Management Fees)	578			549			776
	Net Gains on Securities Transactions	—			—			63
	Total Income	13,994			13,565			13,662
	Expense:
	Interest Expense	620			640			692
	Salaries and Employee Benefits	77			59			75
	Other Expense	754			860			957
	Total Expense	1,451			1,559			1,724
	Income Before Income Tax Benefit and Equity
	in Undistributed Net Income of Subsidiaries	12,543			12,006			11,938
	Income Tax Benefit	473			634			575
	Equity in Undistributed Net Income of Subsidiaries	10,344			9,155			9,666
	Net Income	$	23,360		$	21,795		$	22,179
	The Statement of Changes in Stockholders’ Equity is not reported because it is identical to the Consolidated Statement of Changes in Stockholders’ Equity.
	STATEMENTS OF CASH FLOWS	Years Ended December 31,
		2014			2013			2012
	Cash Flows from Operating Activities:
	Net Income	$	23,360		$	21,795		$	22,179
	Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
	Undistributed Net Income of Subsidiaries	(10,344		)	(9,155		)	(9,666		)
	Net Gains on the Sale of Securities Available-for-Sale	—			—			(63		)
	Shares Issued Under the Directors’ Stock Plan	197			198			175
	Stock-Based Compensation Expense	360			372			424
	Changes in Other Assets and Other Liabilities	(1,014		)	(990		)	(1,640		)
	Net Cash Provided by Operating Activities	12,559			12,220			11,409
	Cash Flows from Investing Activities:
	Proceeds from the Sale of Securities Available-for-Sale	45			45			681
	Purchases of Securities Available-for-Sale	(45		)	(45		)	(359		)
	Net Cash Provided by Investing Activities	—			—			322
	Cash Flows from Financing Activities:
	Stock Options Exercised	1,942			1,254			2,105
	Shares Issued Under the Employee Stock Purchase Plan	—			477			484
	Shares Issued for Dividend Reinvestment Plans	—			1,280			1,822
	Tax Benefit for Exercises of Stock Options	25			23			68
	Purchase of Treasury Stock	(2,455		)	(1,709		)	(4,877		)
	Cash Dividends Paid	(12,407		)	(12,109		)	(11,815		)
	Net Cash Used in Financing Activities	(12,895		)	(10,784		)	(12,213		)
	Net (Decrease) Increase in Cash and Cash Equivalents	(336		)	1,436			(482		)
	Cash and Cash Equivalents at Beginning of the Year	3,349			1,913			2,395
	Cash and Cash Equivalents at End of the Year	$	3,013		$	3,349		$	1,913
	Supplemental Disclosures to Statements of
	Cash Flow Information:
	Interest Paid	$	620		$	640		$	692
	Non-cash Investing and Financing Activities:
Shares Issued for Acquisition of Subsidiary	91			233			233

Cash_and_Cash_Equivalents_Deta

Cash and Cash Equivalents (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Cash and Cash Equivalents [Abstract]
Cash and Due from Banks	$35,081	$37,275
Interest-Bearing Deposits at Banks	11,214	12,705
Total Cash and Cash Equivalents	46,295	49,980	48,832	43,736
Total required reserves, including vault cash and Federal Reserve Bank deposits	$19,989	$18,879

Investment_Securities_Schedule

Investment Securities Schedule of Available for Sale Securities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	$361,962	$453,675
Available-for-sale Securities	366,139	457,606
Gross Unrealized Gains	4,636	5,078
Gross Unrealized Losses	459	1,147
Available-for-sale Securities, Pledged as Collateral	267,384	243,769
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	33,454
From 1 - 5 Years	303,037
From 5 - 10 Years	22,711
Over 10 Years	1,640
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	33,524
From 1 - 5 Years	306,483
From 5 - 10 Years	23,438
Over 10 Years	1,440
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	43,022	113,196
12 Months of Longer	54,339	56,350
Total	97,361	169,546
Number of Securities in a Continuous Loss Position	105	165
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	48	656
12 Months or Longer	411	491
Total	459	1,147
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Gains	208	2
Gross Unrealized Losses	145	395
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	0
From 1 - 5 Years	137,540
From 5 - 10 Years	0
Over 10 Years	0
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	0
From 1 - 5 Years	137,603
From 5 - 10 Years	0
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	39,631	60,664
12 Months of Longer	28,020	33,849
Total	67,651	94,513
Number of Securities in a Continuous Loss Position	22	26
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	48	336
12 Months or Longer	97	59
Total	145	395
U.S. Agency Obligations [Member] | Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	137,540	136,868
Available-for-sale Securities	137,603	136,475
State and Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	81,582	127,224
Available-for-sale Securities	81,730	127,389
Gross Unrealized Gains	187	306
Gross Unrealized Losses	39	141
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	28,273
From 1 - 5 Years	51,384
From 5 - 10 Years	1,285
Over 10 Years	640
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	28,329
From 1 - 5 Years	51,476
From 5 - 10 Years	1,285
Over 10 Years	640
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	3,309	29,967
12 Months of Longer	14,035	4,597
Total	17,344	34,564
Number of Securities in a Continuous Loss Position	65	107
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	0	120
12 Months or Longer	39	21
Total	39	141
Mortgage-Backed Securities - Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	124,732	171,321
Available-for-sale Securities	128,827	175,778
Gross Unrealized Gains	4,100	4,714
Gross Unrealized Losses	5	257
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	2,878
From 1 - 5 Years	100,428
From 5 - 10 Years	21,426
Over 10 Years	0
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	2,888
From 1 - 5 Years	103,786
From 5 - 10 Years	22,153
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	82	15,190
12 Months of Longer	1,546	11,841
Total	1,628	27,031
Number of Securities in a Continuous Loss Position	3	13
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	0	108
12 Months or Longer	5	149
Total	5	257
Mortgage-Backed Securities - Residential [Member] | Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	23,000	31,500
Available-for-sale Securities	23,600	32,200
Mortgage-Backed Securities - Residential [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	101,700	139,800
Available-for-sale Securities	105,200	143,600
Corporate and Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	16,988	17,142
Available-for-sale Securities	16,725	16,798
Gross Unrealized Gains	7	10
Gross Unrealized Losses	270	354
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	2,303
From 1 - 5 Years	13,685
From 5 - 10 Years	0
Over 10 Years	1,000
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	2,307
From 1 - 5 Years	13,618
From 5 - 10 Years	0
Over 10 Years	800
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	0	7,375
12 Months of Longer	10,738	6,063
Total	10,738	13,438
Number of Securities in a Continuous Loss Position	15	19
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	0	92
12 Months or Longer	270	262
Total	270	354
Mututal Funds and Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-For-Sale Securities, at Amortized Cost	1,120	1,120
Available-for-sale Securities	1,254	1,166
Gross Unrealized Gains	134	46
Gross Unrealized Losses	0	0
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year
From 1 - 5 Years
From 5 - 10 Years
Over 10 Years
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year
From 1 - 5 Years
From 5 - 10 Years
Over 10 Years
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	0	0
12 Months of Longer	0	0
Total	0	0
Number of Securities in a Continuous Loss Position	0	0
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	0	0
12 Months or Longer	0	0
Total	$0	$0

Investment_Securities_Schedule1

Investment Securities Schedule of Held to Maturity Securities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities	$302,024	$299,261
Held-to-maturity Securities, at Fair Value	308,566	302,305
Gross Unrealized Gains	6,705	4,786
Gross Unrealized Losses	163	1,742
Held-to-maturity Securities, Pledged as Collateral	282,640	298,261
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	34,163
From 1 - 5 Years	125,515
From 5 - 10 Years	139,297
Over 10 Years	3,049
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	34,236
From 1 - 5 Years	128,281
From 5 - 10 Years	142,909
Over 10 Years	3,140
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	6,724	108,972
12 Months or Longer	16,033	5,111
Total	22,757	114,083
Number of Securities in a Continuous Loss Position	75	137
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	25	1,683
12 Months or Longer	138	59
Total	163	1,742
State and Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities	188,472	198,206
Held-to-maturity Securities, at Fair Value	193,252	202,390
Gross Unrealized Gains	4,935	4,762
Gross Unrealized Losses	155	578
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	34,163
From 1 - 5 Years	88,866
From 5 - 10 Years	63,394
Over 10 Years	2,049
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	34,236
From 1 - 5 Years	91,148
From 5 - 10 Years	65,728
Over 10 Years	2,140
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	2,143	23,633
12 Months or Longer	16,033	5,111
Total	18,176	28,744
Number of Securities in a Continuous Loss Position	74	101
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	17	519
12 Months or Longer	138	59
Total	155	578
Mortgage-Backed Securities - Residential [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities	112,552
Held-to-maturity Securities, at Fair Value	114,314
Gross Unrealized Gains	1,770	24
Gross Unrealized Losses	8	1,164
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	0
From 1 - 5 Years	36,649
From 5 - 10 Years	75,903
Over 10 Years	0
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	0
From 1 - 5 Years	37,133
From 5 - 10 Years	77,181
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	4,581	85,339
12 Months or Longer	0	0
Total	4,581	85,339
Number of Securities in a Continuous Loss Position	1	36
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	8	1,164
12 Months or Longer	0	0
Total	8	1,164
Mortgage-Backed Securities - Residential [Member] | Agency Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities	4,400
Held-to-maturity Securities, at Fair Value	4,500
Mortgage-Backed Securities - Residential [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities	108,100	100,055
Held-to-maturity Securities, at Fair Value	109,800	98,915
Corporate and Other Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities	1,000	1,000
Held-to-maturity Securities, at Fair Value	1,000	1,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Maturities of Debt Securities, at Amortized Cost [Abstract]
Within One Year	0
From 1 - 5 Years	0
From 5 - 10 Years	0
Over 10 Years	1,000
Maturities of Debt Securities, at Fair Value [Abstract]
Within One Year	0
From 1 - 5 Years	0
From 5 - 10 Years	0
Over 10 Years	1,000
Securities in a Continuous Loss Position, at Fair Value [Abstract]
Less than 12 Months	0	0
12 Months or Longer	0	0
Total	0	0
Number of Securities in a Continuous Loss Position	0	0
Unrealized Losses on Securities in a Continuous Loss Position [Abstract]
Less than 12 Months	0	0
12 Months or Longer	0	0
Total	$0	$0

Investment_Securities_CostMeth

Investment Securities Cost-Method Investments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments, All Other Investments [Abstract]
Federal Reserve Bank Stock	$1,048	$1,035
Federal Home Loan Bank Stock	3,803	5,246
Federal Home Loan Bank and Federal Reserve Bank Stock	$4,851	$6,281

Loans_Loan_Categories_and_Past

Loans Loan Categories and Past Due Loans(Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	$5,205	$4,303
Loans Past Due 60 - 89 Days	2,881	4,388
Loans Past Due 90 or More Days	5,382	5,422
Total Loans Past Due	13,468	14,113
Current Loans	1,399,800	1,252,359
Total Loans	1,413,268	1,266,472
Loans 90 or More Days Past Due and Still Accruing Interest	537	652
Nonaccrual Loans	6,899	6,479
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	124	304
Loans Past Due 60 - 89 Days	154	601
Loans Past Due 90 or More Days	345	177
Total Loans Past Due	623	1,082
Current Loans	98,888	86,811
Total Loans	99,511	87,893
Loans 90 or More Days Past Due and Still Accruing Interest	0	28
Nonaccrual Loans	473	352
Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	0	0
Loans Past Due 60 - 89 Days	0	0
Loans Past Due 90 or More Days	0	0
Total Loans Past Due	0	0
Current Loans	18,815	27,815
Total Loans	18,815	27,815
Loans 90 or More Days Past Due and Still Accruing Interest	0	0
Nonaccrual Loans	0	0
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	432	200
Loans Past Due 60 - 89 Days	7	1,200
Loans Past Due 90 or More Days	1,832	2,034
Total Loans Past Due	2,271	3,434
Current Loans	319,026	284,685
Total Loans	321,297	288,119
Loans 90 or More Days Past Due and Still Accruing Interest	0	0
Nonaccrual Loans	2,071	2,048
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	30	37
Loans Past Due 60 - 89 Days	4	19
Loans Past Due 90 or More Days	3	0
Total Loans Past Due	37	56
Current Loans	7,628	7,593
Total Loans	7,665	7,649
Loans 90 or More Days Past Due and Still Accruing Interest	0	0
Nonaccrual Loans	4	0
Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	4,137	3,233
Loans Past Due 60 - 89 Days	1,221	1,041
Loans Past Due 90 or More Days	203	98
Total Loans Past Due	5,561	4,372
Current Loans	423,815	389,832
Total Loans	429,376	394,204
Loans 90 or More Days Past Due and Still Accruing Interest	0	0
Nonaccrual Loans	411	219
Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Past Due 30 - 59 Days	482	529
Loans Past Due 60 - 89 Days	1,495	1,527
Loans Past Due 90 or More Days	2,999	3,113
Total Loans Past Due	4,976	5,169
Current Loans	531,628	455,623
Total Loans	536,604	460,792
Loans 90 or More Days Past Due and Still Accruing Interest	537	624
Nonaccrual Loans	$3,940	$3,860

Loans_Allowance_for_Loan_Losse

Loans Allowance for Loan Losses (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	$14,434	$15,298	$15,003
Charge-offs	-1,021	-1,411	-782
Recoveries	309	347	232
Provision	1,848	200	845
Allowance for Credit Losses, Ending Balance	15,570	14,434	15,298
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	109	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	15,461	14,434
Ending Loan Balance - Individually Evaluated for Impairment	4,341	4,488
Ending Loan Balance - Collectively Evaluated for Impairment	1,408,927	1,261,984
Commercial [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	1,886	2,344	1,927
Charge-offs	-212	-926	-90
Recoveries	86	88	23
Provision	340	380	484
Allowance for Credit Losses, Ending Balance	2,100	1,886	2,344
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	0	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	2,100	1,886
Ending Loan Balance - Individually Evaluated for Impairment	494	221
Ending Loan Balance - Collectively Evaluated for Impairment	99,017	87,672
Commercial Construction [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	417	601	602
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	-135	-184	-1
Allowance for Credit Losses, Ending Balance	282	417	601
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	0	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	282	417
Ending Loan Balance - Individually Evaluated for Impairment	0	0
Ending Loan Balance - Collectively Evaluated for Impairment	18,815	27,815
Commercial Real Estate [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	3,545	3,050	3,136
Charge-offs	0	-11	-206
Recoveries	0	0	0
Provision	301	506	120
Allowance for Credit Losses, Ending Balance	3,846	3,545	3,050
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	0	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	3,846	3,545
Ending Loan Balance - Individually Evaluated for Impairment	1,492	1,785
Ending Loan Balance - Collectively Evaluated for Impairment	319,805	286,334
Other Consumer [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	272	304	350
Charge-offs	-41	-28	-52
Recoveries	6	3	9
Provision	22	-7	-3
Allowance for Credit Losses, Ending Balance	259	272	304
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	0	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	259	272
Ending Loan Balance - Individually Evaluated for Impairment	0	0
Ending Loan Balance - Collectively Evaluated for Impairment	7,665	7,649
Automobile [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	4,206	4,536	4,496
Charge-offs	-677	-431	-401
Recoveries	217	256	200
Provision	1,205	-155	241
Allowance for Credit Losses, Ending Balance	4,951	4,206	4,536
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	0	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	4,951	4,206
Ending Loan Balance - Individually Evaluated for Impairment	118	173
Ending Loan Balance - Collectively Evaluated for Impairment	429,258	394,031
Residential [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	3,026	3,405	3,414
Charge-offs	-91	-15	-33
Recoveries	0	0	0
Provision	434	-364	24
Allowance for Credit Losses, Ending Balance	3,369	3,026	3,405
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	109	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	3,260	3,026
Ending Loan Balance - Individually Evaluated for Impairment	2,237	2,309
Ending Loan Balance - Collectively Evaluated for Impairment	534,367	458,483
Unallocated [Member]
Rollfoward of the Allowance for Loan Losses for the Quarterly Report [Roll Forward]
Allowance for Credit Losses, Beginning Balance	1,082	1,058	1,078
Charge-offs		0	0
Recoveries		0	0
Provision	-319	24	-20
Allowance for Credit Losses, Ending Balance	763	1,082	1,058
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for Loan Losses - Individually Evaluated for Impairment	0	0
Allowance for Loan Losses - Collectively Evaluated for Impairment	763	1,082
Ending Loan Balance - Individually Evaluated for Impairment	0	0
Ending Loan Balance - Collectively Evaluated for Impairment	$0	$0

Loans_Loan_Credit_Quality_Indi

Loans Loan Credit Quality Indicators (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	$403,696	$375,393
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	6,160	838
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	29,767	27,596
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0
Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	968,753	857,942
Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	4,892	4,703
Commercial [Member] | Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	85,949	79,966
Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	2,442	204
Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	11,120	7,723
Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0
Commercial Construction [Member] | Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	18,815	27,815
Commercial Construction [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0
Commercial Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0
Commercial Construction [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0
Commercial Real Estate [Member] | Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	298,932	267,612
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	3,718	634
Commercial Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	18,647	19,873
Commercial Real Estate [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	0	0
Other Consumer [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	7,661	7,649
Other Consumer [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	4	0
Automobile [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	428,965	393,985
Automobile [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	411	219
Residential [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	532,127	456,308
Residential [Member] | Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Net	$4,477	$4,484

Loans_Impaired_Loans_Details

Loans Impaired Loans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Recorded Investment [Abstract]
With No Related Allowance	$3,782	$4,488
With a Related Allowance	559	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	3,782	4,488
With a Related Allowance	559	0
Average Recorded Balance [Abstract]
With No Related Allowance	3,634	4,178	4,132
With a Related Allowance	546	694	694
Interest Income Recognized [Abstract]
With No Related Allowance	19	21	91
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	64
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	109
Commercial [Member]
Recorded Investment [Abstract]
With No Related Allowance	494	221
With a Related Allowance	0	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	494	221
With a Related Allowance	0	0
Average Recorded Balance [Abstract]
With No Related Allowance	348	133	56
With a Related Allowance	0	694	694
Interest Income Recognized [Abstract]
With No Related Allowance	11	4	6
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	0
Commercial Construction [Member]
Recorded Investment [Abstract]
With No Related Allowance	0	0
With a Related Allowance	0	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	0	0
With a Related Allowance	0	0
Average Recorded Balance [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Interest Income Recognized [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	0
Commercial Real Estate [Member]
Recorded Investment [Abstract]
With No Related Allowance	1,492	1,785
With a Related Allowance	0	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	1,492	1,785
With a Related Allowance	0	0
Average Recorded Balance [Abstract]
With No Related Allowance	1,492	2,157	2,241
With a Related Allowance	0	0	0
Interest Income Recognized [Abstract]
With No Related Allowance	0	0	64
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	64
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	0
Other Consumer [Member]
Recorded Investment [Abstract]
With No Related Allowance	0	0
With a Related Allowance	0	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	0	0
With a Related Allowance	0	0
Average Recorded Balance [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Interest Income Recognized [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	0
Automobile [Member]
Recorded Investment [Abstract]
With No Related Allowance	118	173
With a Related Allowance	0	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	118	173
With a Related Allowance	0	0
Average Recorded Balance [Abstract]
With No Related Allowance	121	188	236
With a Related Allowance	0	0	0
Interest Income Recognized [Abstract]
With No Related Allowance	7	9	12
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	0
Residential [Member]
Recorded Investment [Abstract]
With No Related Allowance	1,678	2,309
With a Related Allowance	559	0
Unpaid Principal Balance [Abstract]
With No Related Allowance	1,678	2,309
With a Related Allowance	559	0
Average Recorded Balance [Abstract]
With No Related Allowance	1,673	1,700	1,599
With a Related Allowance	546	0	0
Interest Income Recognized [Abstract]
With No Related Allowance	1	8	9
With a Related Allowance	0	0	0
Cash Basis Income [Abstract]
With No Related Allowance	0	0	0
With a Related Allowance	0	0	0
Impaired Financing Receivable, Related Allowance	$109

Loans_Loans_Modified_in_Troubl

Loans Loans Modified in Trouble Debt Restructurings (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Number of Loans	5	10	19
Pre-Modification Outstanding Recorded Investment	$610	$257	$207
Post-Modification Outstanding Recorded Investment	610	288	207
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	0	0	0
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	1	0
Pre-Modification Outstanding Recorded Investment	0	169	0
Post-Modification Outstanding Recorded Investment	0	200	0
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	0	0	0
Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0	0
Pre-Modification Outstanding Recorded Investment	0	0	0
Post-Modification Outstanding Recorded Investment	0	0	0
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	0	0	0
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0	2
Pre-Modification Outstanding Recorded Investment	0	0	47
Post-Modification Outstanding Recorded Investment	0	0	47
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	0	0	0
Other Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0	0
Pre-Modification Outstanding Recorded Investment	0	0	0
Post-Modification Outstanding Recorded Investment	0	0	0
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	0	0	0
Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	9	17
Pre-Modification Outstanding Recorded Investment	36	88	160
Post-Modification Outstanding Recorded Investment	36	88	160
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	0	0	0
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	0	0
Pre-Modification Outstanding Recorded Investment	574	0	0
Post-Modification Outstanding Recorded Investment	574	0	0
Subsequent Default, Number of Contracts	0	0	0
Subsequent Default, Recorded Investment	0	0	0
Commitments to lend additional funds to modified loans	$0	$0	$0

Loans_Supplemental_Loan_Inform

Loans Supplemental Loan Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$2,771	$2,152
Deposit Liabilities Reclassified as Loans Receivable	973	501
Loans Pledged as Collateral	313,355	270,372
Residential Real Estate Loans Serviced for Freddie Mac	158,598	156,593
Disposal Group, Including Discontinued Operation, Mortgage Loans	398	64
Loans to Related Parties [Roll Forward]
Balance at beginning of year	7,769	17,447
Adjustment due to change in composition of related parties	0	-8,819
New loans and renewals, during the year	694	2,253
Repayments, during the year	-2,460	-3,112
Balance at end of year	$6,003	$7,769

Premises_and_Equipment_Details

Premises and Equipment (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Total Cost	$58,283	$57,155
Accumulated Depreciation and Amortization	-29,795	-28,001
Net Premises and Equipment	28,488	29,154
Land and Bank Premises [Member]
Property, Plant and Equipment [Line Items]
Total Cost	35,062	35,114
Equipment, Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Total Cost	22,003	20,851
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total Cost	$1,218	$1,190

Premises_and_Equipment_Supplem

Premises and Equipment Supplemental Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Depreciation	$2,238	$1,928	$1,521

Other_Intangible_Assets_Schedu

Other Intangible Assets Schedule of Finite-Lived Intangible Assets (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$8,413		$8,280
Accumulated Amortization	-4,788		-4,140
Net Carrying Amount	3,625		4,140		4,492
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Beginning Balance	4,140		4,492		4,749
Intangible Assets Acquired	133		331		417
Amortization of Intangible Assets	-648		-683		-674
Finite-Lived Intangible Assets, Ending Balance	3,625		4,140		4,492
Depositor Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,247	[1]	2,247	[1]
Accumulated Amortization	-2,237	[1]	-2,186	[1]
Net Carrying Amount	10	[1]	61	[1]	153	[1]
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Beginning Balance	61	[1]	153	[1]	286	[1]
Intangible Assets Acquired	0	[1]	0	[1]	0	[1]
Amortization of Intangible Assets	-51	[1]	-92	[1]	-133	[1]
Finite-Lived Intangible Assets, Ending Balance	10	[1]	61	[1]	153	[1]
Mortgage Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,715	[2]	1,582	[2]
Accumulated Amortization	-883	[2]	-622	[2]
Net Carrying Amount	832	[2]	960	[2]	859	[2]
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Beginning Balance	960	[2]	859	[2]	599	[2]
Intangible Assets Acquired	133	[2]	331	[2]	417	[2]
Amortization of Intangible Assets	-261	[2]	-230	[2]	-157	[2]
Finite-Lived Intangible Assets, Ending Balance	832	[2]	960	[2]	859	[2]
Customer Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,451	[1]	4,451	[1]
Accumulated Amortization	-1,668	[1]	-1,332	[1]
Net Carrying Amount	2,783	[1]	3,119	[1]	3,480	[1]
Finite-lived Intangible Assets [Roll Forward]
Finite-Lived Intangible Assets, Beginning Balance	3,119	[1]	3,480	[1]	3,864	[1]
Intangible Assets Acquired	0	[1]	0	[1]	0	[1]
Amortization of Intangible Assets	-336	[1]	-361	[1]	-384	[1]
Finite-Lived Intangible Assets, Ending Balance	$2,783	[1]	$3,119	[1]	$3,480	[1]
[1]	Amortization of depositor intangibles and customer intangibles are reported in the consolidated statements of income as a component of other operating expense.
[2]	Amortization of mortgage servicing rights is reported in the consolidated statements of income as a reduction of mortgage servicing fee income, which is included with fees for other services to customers.

Other_Intangible_Assets_Schedu1

Other Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
In Thousands, unless otherwise specified
Estimated Annual Amoritzation Expense: [Abstract]
2015	$581
2016	533
2017	453
2018	381
2019	290
Later Years	1,387
Net Carrying Amount	3,625		4,140		4,492		4,749
Depositor Intangibles [Member]
Estimated Annual Amoritzation Expense: [Abstract]
2015	10	[1]
2016	0	[1]
2017	0	[1]
2018	0	[1]
2019	0	[1]
Later Years	0	[1]
Net Carrying Amount	10	[1]	61	[1]	153	[1]	286	[1]
Mortgage Servicing Rights [Member]
Estimated Annual Amoritzation Expense: [Abstract]
2015	252	[2]
2016	232	[2]
2017	172	[2]
2018	118	[2]
2019	45	[2]
Later Years	13	[2]
Net Carrying Amount	832	[2]	960	[2]	859	[2]	599	[2]
Customer Intangibles [Member]
Estimated Annual Amoritzation Expense: [Abstract]
2015	319	[1]
2016	301	[1]
2017	281	[1]
2018	263	[1]
2019	245	[1]
Later Years	1,374	[1]
Net Carrying Amount	$2,783	[1]	$3,119	[1]	$3,480	[1]	$3,864	[1]
[1]	Amortization of depositor intangibles and customer intangibles are reported in the consolidated statements of income as a component of other operating expense.
[2]	Amortization of mortgage servicing rights is reported in the consolidated statements of income as a reduction of mortgage servicing fee income, which is included with fees for other services to customers.

Guarantees_Details

Guarantees (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Guarantees [Abstract]
Commitments to Extend Credit, Nominal Amount	$249,803	$237,940
Standby Letters of Credit, Nominal Amount	3,317	3,345
Commitments to Extend Credit, Fair Value	0	0
Standby Letters of Credit, Fair Value	$39	$65

Time_Deposits_Details

Time Deposits (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Year of Maturity
2015	$124,406
2016	28,487
2017	19,869
2018	11,845
2019	17,126
2020 and Beyond	4,110
Total	$205,843

Debt_Schedule_of_Short_Term_De

Debt Schedule of Short Term Debt (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Short-term Debt [Line Items]
Short-term Borrowings	$60,421	$64,777
Overnight Advances from the Federal Home Loan Bank of New York [Member]
Short-term Debt [Line Items]
Short-term Borrowings	41,000	53,000
Maximum Borrowing Capacity	203,885	214,000
Securities Sold under Agreements to Repurchase [Member]
Short-term Debt [Line Items]
Short-term Borrowings	19,421	11,777
Federal Funds Purchased [Member]
Short-term Debt [Line Items]
Maximum Borrowing Capacity	35,000	30,000
Federal Reserve Bank of New York [Member]
Short-term Debt [Line Items]
Maximum Borrowing Capacity	$307,159	$302,000

Debt_Maturities_of_Long_Term_D

Debt Maturities of Long Term Debt (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Long-term Debt, Fiscal Year Maturity [Abstract]
Final Maturity Balances - First Year	$10,000	$10,000
Final Maturity Balances - Second Year	0	10,000
Final Maturity Balances - Third Year	0	0
Final Maturity Balances - Total	$10,000	$20,000
Final Maturity Weighted Average Rate - First Year	3.88%	1.43%
Final Maturity Weighted Average Rate - Second Year	0.00%	3.88%
Final Maturity Weighted Average Rate - Third Year	0.00%	0.00%
Final Maturity Weighted Average Rate - Total	3.88%	2.66%

Debt_Schedule_of_Longterm_Debt

Debt Schedule of Long-term Debt instruments (Details) (Junior Subordinated Debt [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ACST II [Member]
Debt Instrument [Line Items]
Balance at December 31,	$10,000	$10,000
Period-End Interest Rate	3.38%	3.40%
ACST III [Member]
Debt Instrument [Line Items]
Balance at December 31,	$10,000	$10,000
Period-End Interest Rate	2.23%	2.25%

Comprehensive_Income_Other_Com

Comprehensive Income Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	($2,961)	$3,500	($2,246)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	168	589	479
Other Comprehensive Income (Loss), before Tax	-4,547	6,772	-2,925
Other Comprehensive Income (Loss), Tax	1,754	-2,683	1,158
Other Comprehensive (Loss) Income	-2,793	4,089	-1,767
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Schedule of Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	356	-4,843	-1,094
Other Comprehensive Income Loss Before Reclassifications Tax (Expense) Benefit	-124	1,918	433
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	232	-2,925	-661
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	-110	-540	-865
Reclassification From Accumulated Other Comprehensive Income Current Period Tax (Expense) Benefit	43	214	343
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-67	-326	-522
Other Comprehensive (Loss) Income	165	-3,251	-1,183
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Schedule of Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	-4,610	10,640	-2,218
Other Comprehensive Income Loss Before Reclassifications Tax (Expense) Benefit	1,764	-4,215	878
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-2,846	6,425	-1,340
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	474	1,513	1,677
Reclassification From Accumulated Other Comprehensive Income Current Period Tax (Expense) Benefit	-186	-599	-664
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	288	914	1,013
Other Comprehensive (Loss) Income	-2,558	7,339	-327
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Schedule of Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, before Tax	-570		-405
Other Comprehensive Income Loss Before Reclassifications Tax (Expense) Benefit	223		160
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-347	0	-245
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	-87	2	-20
Reclassification From Accumulated Other Comprehensive Income Current Period Tax (Expense) Benefit	34	-1	8
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-53	1	-12
Other Comprehensive (Loss) Income	($400)	$1	($257)

Comprehensive_Income_Changes_i

Comprehensive Income Changes in Accumulated Other Comprehensive Income By Componenet (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	($7,166)	($4,373)	($8,462)	$6,695
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-2,961	3,500	-2,246
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	168	589	479
Other Comprehensive (Loss) Income	-2,793	4,089	-1,767
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	2,539	2,374	5,625	6,808
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	232	-2,925	-661
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-67	-326	-522
Other Comprehensive (Loss) Income	165	-3,251	-1,183
Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	-9,255	-6,697	-14,036	-13,709
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-2,846	6,425	-1,340
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	288	914	1,013
Other Comprehensive (Loss) Income	-2,558	7,339	-327
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss	-450	-50	-51	206
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-347	0	-245
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-53	1	-12
Other Comprehensive (Loss) Income	($400)	$1	($257)

Comprehensive_Income_Reclassif

Comprehensive Income Reclassification Out of Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for Income Taxes	$10,174	$9,079	$9,661
Net Income (Loss) Available to Common Stockholders, Basic	-168	-589	-479
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	110	540	865
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	110	540	865
Provision for Income Taxes	-43	-214	-343
Net Income (Loss) Available to Common Stockholders, Basic	67	326	522
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax	87	-2	20
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax	-474	-1,513	-1,677
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	-387	-1,515	-1,657
Provision for Income Taxes	152	600	656
Net Income (Loss) Available to Common Stockholders, Basic	($235)	($915)	($1,001)

Stock_Based_Compensation_Roll_

Stock Based Compensation Roll Forward Schedule of Stock Option Plan by Shares and Weighted Average Exercise Prices (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Roll Forward of Shares Outstanding [Roll Forward]
Outstanding, Beginning Balance, in shares	397,177
Granted, in shares	75,518	10,404	78,848
Exercised, in shares	-62,269
Forfeited, in shares	-8,984
Outstanding, Ending Balance, in shares	401,442	397,177
Exercisable at December 31, 2014, in shares	266,654
Vested and Expected to Vest, in shares	134,788
Roll Forward of Shares Outstanding - Weighted Average Exercise Price: [Roll Forward]
Outstanding, Beginning Balance, in Weighted Average Exercise Price,	$22.44
Granted, in Weighted Average Exercise Price	$24.51
Exercised, in Weighted Average Exercise Price	$23.35
Forfeited, in Weighted Average Exercise Price	$23.89
Outstanding, Ending Balance, in Weighted Average Exercise Price,	$22.66	$22.44
Exercisable at December 31, 2014, in Weighted Average Exercise Price	$21.74
Vested and Expected to Vest, in Weighted Average Exercise Price	$24.47
Outstanding at December 31, 2014, Weighted Average Remaining Contractual Life, in years	5 years 9 months 28 days
Exercisable at December 31, 2014, Weighted Average Remaining Contractual Life, in years	4 years 8 months 3 days
Vested and Expected to Vest, Weighted Average Remaining Contractual Life, in years	8 years 1 month 16 days
Outstanding at December 31, 2014, Aggregate Intrinsic Value	$1,939
Exercisable at December 31, 2014, Aggregate Intrinsic Value	1,533
Vested and Expected to Vest, Aggregate Intrinsic Value	$406
Shares Available for Grant at Period End, in shares	445,000

Stock_Based_Compensation_Sched

Stock Based Compensation Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	401,442
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	5 years 9 months 28 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$22.55
Number of Shares Outstanding, Exercisable Options, in shares	266,654
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	4 years 8 months 3 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$21.74
Exercise Price Range $18.71 to $19.48 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	72,516
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	3 years 8 months 10 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$19.24
Number of Shares Outstanding, Exercisable Options, in shares	72,516
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	3 years 8 months 10 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$19.24
Exercise Price Range $20.82 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	27,470
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	1 year 11 months 2 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$20.82
Number of Shares Outstanding, Exercisable Options, in shares	27,470
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	1 year 11 months 2 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$20.82
Exercise Price Range $21.83 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	64,829
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	5 years 0 months 28 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$21.83
Number of Shares Outstanding, Exercisable Options, in shares	64,829
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	5 years 0 months 28 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$21.83
Exercise Price Range $23.30 to $23.95 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	153,236
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	6 years 7 months 27 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$23.61
Number of Shares Outstanding, Exercisable Options, in shares	92,333
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	6 years 5 months 10 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$23.56
Exercise Price Range $24.51 to $25.27 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares Outstanding, Outstanding Options, in shares	83,391
Weighted-Average Remaining Contractual Life, Outstanding Options, in years	8 years 0 months 18 days
Weighted Average Exercise Price, Outstanding Options, in Weighted Average Exercise Price	$24.60
Number of Shares Outstanding, Exercisable Options, in shares	9,506
Weighted-Average Remaining Contractual Life, Exercisable Options, in years	8 years 0 months 18 days
Weighted-Average Exercise Price, Exercisable Options, in Weighted Average Exercise Price	$25.27

Stock_Based_Compensation_Sched1

Stock Based Compensation Schedule of Other Stock Option Plan Information (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Granted, in shares	75,518	10,404	78,848
Fair Value of Options Granted, Weighted Average Grant Date, in dollars per share	$5.92	$5.35	$5.77
Dividend Yield	3.97%	4.20%	3.93%
Expected Volatility	35.30%	36.57%	37.43%
Risk Free Interest Rate	2.19%	1.31%	1.22%
Expected Life, in years	6 years 10 months 6 days	6 years 8 months 15 days	6 years 5 months 16 days
Stock-Based Compensation Expense	$360	$372	$424
Compensation Costs for Non-vested Awards Not Yet Recognized	478	420	737
Weighted Average Expected Vesting Period, In Years	1 year 8 months 5 days	1 year 5 months 13 days	1 year 8 months 15 days
Proceeds From Stock Options Exercised	1,454	1,254	2,105
Tax Benefit for Disposition of Stock Options	25	23	68
Intrinsic Value of Stock Options Exercised	$170	$267	$2,434

Stock_Based_Compensation_Sched2

Stock Based Compensation Schedule of Employee Stock Ownership Plans (ESOP) Disclosure (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Stock Ownership Plan (ESOP), Shares in ESOP [Abstract]
ESOP Compensation Expense	$800	$600	$550
Allocated Shares, in shares	690,853
Shares Released for Allocation During 2012, in shares	17,300
Unallocated Shares, in shares	71,748
Total ESOP Shares, in shares	779,901
Market Value of Unallocated ESOP Shares	$1,972

Retirement_Benefit_Plans_Detai

Retirement Benefit Plans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		$45,704		$44,653
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		44,653
Fair Value of Plan Assets, End of Period		45,704		44,653
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		45,704		44,653
Percent of Total		100.00%		100.00%
Expected Future Benefit Payments [Abstract]
Health Care Cost Trend Rate Assumed for Next Year		8.00%		8.50%
Rate to which the Cost Trend Rate is Assumed to Decline (the Ultimate Trend Rate)		3.89%		5.00%
Year that the Rate Reaches the Ultimate Trend Rate		2075		2021
Effect of One Percentage Point Increase on Service and Interest Cost Components		60
Effect of One Percentage Point Decrease on Service and Interest Cost Components		-49
Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation		782
Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation		-664
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		45,704		44,653
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		45,704		44,653
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		45,704		44,653
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Cash and Cash Equivalents [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		20		7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		7
Fair Value of Plan Assets, End of Period		20		7
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		20		7
Percent of Total		0.00%		0.00%
Target Allocation Minimum, Percentage		0.00%		0.00%
Target Allocation Maximum, Percentage		15.00%		15.00%
Cash and Cash Equivalents [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		20		7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		20		7
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		20		7
Cash and Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Cash and Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Money Market Funds [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		4,322		3,941
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		3,941
Fair Value of Plan Assets, End of Period		4,322		3,941
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		4,322		3,941
Percent of Total		9.50%		8.80%
Target Allocation Minimum, Percentage		0.00%		0.00%
Target Allocation Maximum, Percentage		15.00%		15.00%
Money Market Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		4,322		3,941
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		4,322		3,941
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		4,322		3,941
Money Market Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Money Market Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Common Stock
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		4,551		4,291
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		4,291
Fair Value of Plan Assets, End of Period		4,551		4,291
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		4,551		4,291
Percent of Total		10.00%	[1]	9.60%
Target Allocation Minimum, Percentage		0.00%		0.00%
Target Allocation Maximum, Percentage		10.00%		10.00%
Common Stock | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		4,551		4,291
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		4,551		4,291
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		4,551		4,291
Common Stock | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Common Stock | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Equity Funds [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		29,929		31,757
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		31,757
Fair Value of Plan Assets, End of Period		29,929		31,757
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		29,929		31,757
Percent of Total		65.40%		71.20%
Target Allocation Minimum, Percentage		66.00%		55.00%
Target Allocation Maximum, Percentage		85.00%		85.00%
Equity Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		29,929		31,757
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		29,929		31,757
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		29,929		31,757
Equity Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Equity Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Equity Funds [Member] | North Country Funds - Equity [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		18,975	[2]	17,419	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		17,419	[2]
Fair Value of Plan Assets, End of Period		18,975	[2]	17,419	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		18,975	[2]	17,419	[2]
Percent of Total		41.40%	[2]	39.10%	[2]
Target Allocation Minimum, Percentage
Target Allocation Maximum, Percentage
Equity Funds [Member] | North Country Funds - Equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		18,975	[2]	17,419	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		18,975	[2]	17,419	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		18,975	[2]	17,419	[2]
Equity Funds [Member] | North Country Funds - Equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0	[2]	0	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Equity Funds [Member] | North Country Funds - Equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0	[2]	0	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Equity Funds [Member] | Other Mutual Funds - Equity [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		10,954		14,338
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		14,338
Fair Value of Plan Assets, End of Period		10,954		14,338
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		10,954		14,338
Percent of Total		24.00%		32.10%
Target Allocation Minimum, Percentage
Target Allocation Maximum, Percentage
Equity Funds [Member] | Other Mutual Funds - Equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		10,954		14,338
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		10,954		14,338
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		10,954		14,338
Equity Funds [Member] | Other Mutual Funds - Equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Equity Funds [Member] | Other Mutual Funds - Equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Fixed Income Funds [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		6,882		4,657
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		4,657
Fair Value of Plan Assets, End of Period		6,882		4,657
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		6,882		4,657
Percent of Total		15.10%		10.40%
Target Allocation Minimum, Percentage		15.00%		10.00%
Target Allocation Maximum, Percentage		30.00%		30.00%
Fixed Income Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		6,882		4,657
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		6,882		4,657
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		6,882		4,657
Fixed Income Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Fixed Income Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Fixed Income Funds [Member] | North Country Funds - Fixed Income [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		5,436	[2]	4,309	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		4,309	[2]
Fair Value of Plan Assets, End of Period		5,436	[2]	4,309	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		5,436	[2]	4,309	[2]
Percent of Total		11.90%	[2]	9.60%	[2]
Target Allocation Minimum, Percentage
Target Allocation Maximum, Percentage
Fixed Income Funds [Member] | North Country Funds - Fixed Income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		5,436	[2]	4,309	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		5,436	[2]	4,309	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		5,436	[2]	4,309	[2]
Fixed Income Funds [Member] | North Country Funds - Fixed Income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0	[2]	0	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Fixed Income Funds [Member] | North Country Funds - Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0	[2]	0	[2]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0	[2]	0	[2]
Fixed Income Funds [Member] | Other Mutual Funds - Fixed Income [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		1,446		348
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period		348
Fair Value of Plan Assets, End of Period		1,446		348
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		1,446		348
Percent of Total		3.20%		0.80%
Target Allocation Minimum, Percentage
Target Allocation Maximum, Percentage
Fixed Income Funds [Member] | Other Mutual Funds - Fixed Income [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		1,446		348
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		1,446		348
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		1,446		348
Fixed Income Funds [Member] | Other Mutual Funds - Fixed Income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Fixed Income Funds [Member] | Other Mutual Funds - Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, End of Period		0		0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Fair Value of Plan Assets		0		0
Employees' Pension Plan [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		45,704		44,653		39,880
Benefit Obligation		36,966		33,259		37,046
Funded Status of Plan		8,738		11,394
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation, Beginning of Period	36,966	33,259		37,046
Service Cost		1,410		1,506		1,467
Interest Cost		1,621		1,261		1,436
Plan Participants' Contributions		0		0
Amendments		0		0
Actuarial Loss		2,909		-3,820
Benefits Paid		-2,233		-2,734
Benefit Obligation, End of Period		36,966		33,259		37,046
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period	45,704	44,653		39,880
Actual Return on Plan Assets		3,284		7,507
Contributions to Pension Plans		0		0
Plan Participants' Contributions		0		0
Benefits Paid		-2,233		-2,734
Fair Value of Plan Assets, End of Period		45,704		44,653		39,880
Accumulated Benefit Obligation at December 31, 2012		36,530
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Prepaid Benefit Cost		8,738		11,394
Accrued Benefit Liability		0		0
Net Benefit Cost Recognized		8,738		11,394
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net Retirement Plan Loss, Before-Tax Amount		2,855		-8,438		1,286
Net prior Service Cost Arising During the Period		0		0		0
Amortization of Net Loss		-356		-1,231		-1,387
Accretion of Net Retirement Plan Prior Service Credit, Tax (Expense) Benefit		45		-37		-41
Total Other Comprehensive (Loss) Income for Pension and Other Postretirement Benefit Plans		2,544		-9,706		-142
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net Actuarial Loss		10,856		8,357
Prior Service (Credit) Cost		-210		-255
Total Accumulated Other Comprehensive Income, Before Tax		10,646		8,102
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost		1,410		1,506		1,467
Interest Cost		1,621		1,261		1,436
Expected Return on Plan Assets		-3,230		-2,889		-2,865
Amortization of Prior Service (Credit) Cost		-45		37		41
Amortization of Net Loss		356		1,232		1,387
Net Periodic Benefit Cost		112		1,147		1,466
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate		4.31%		5.10%
Rate of Compensation Increase		3.50%		3.50%
Interest Rate Credit for Determining Projected Cash Balance Account		3.04%		4.00%
Interest Rate to Annuitize Cash Balance Account		4.75%		5.25%
Interest Rate to Convert Annuities to Actuarially Equivalent Lump Sum Account		4.75%		5.25%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount Rate		5.10%		3.55%		4.05%
Expected Long-Term Return on Assets		7.50%		7.50%		7.50%
Rate of Compensation Increase		3.50%		3.50%		3.50%
Interest Rate Credit for Determining Projected Cash Balance Account		4.00%		3.00%		3.25%
Interest Rate to Annuitize Cash Balance Account		5.25%		4.50%		5.00%
Interest Rate to Convert Accuities to Actuarially Equivalent Lump Sum Amounts		5.25%		4.50%		5.00%
Fair Value of Plan Assets		45,704		44,653		39,880
Expected Future Benefit Payments [Abstract]
2015		2,163
2016		2,334
2017		2,356
2018		2,253
2019		2,256
2020 - 2024		12,799
Estimated Contributions During 2015	0
Employees' Pension Plan [Member] | Scenario, Forecast [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net Actuarial Loss	556
Prior Service (Credit) Cost	-83
Select Executive Retirement Plan [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0		0
Benefit Obligation		5,072		4,459		5,324
Funded Status of Plan		-5,072		-4,459
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation, Beginning of Period	5,072	4,459		5,324
Service Cost		10		0		87
Interest Cost		206		163		190
Plan Participants' Contributions		0		0
Amendments		0		0
Actuarial Loss		870		-555
Benefits Paid		-473		-473
Benefit Obligation, End of Period		5,072		4,459		5,324
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period	0	0		0
Actual Return on Plan Assets		0		0
Contributions to Pension Plans		473		473
Plan Participants' Contributions		0		0
Benefits Paid		-473		-473
Fair Value of Plan Assets, End of Period		0		0		0
Accumulated Benefit Obligation at December 31, 2012		5,072
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Prepaid Benefit Cost		0		0
Accrued Benefit Liability		-5,072		-4,459
Net Benefit Cost Recognized		-5,072		-4,459
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net Retirement Plan Loss, Before-Tax Amount		871		-554		441
Net prior Service Cost Arising During the Period		0		0		405
Amortization of Net Loss		-93		-140		-156
Accretion of Net Retirement Plan Prior Service Credit, Tax (Expense) Benefit		-72		-79		-53
Total Other Comprehensive (Loss) Income for Pension and Other Postretirement Benefit Plans		706		-773		637
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net Actuarial Loss		2,452		1,674
Prior Service (Credit) Cost		570		642
Total Accumulated Other Comprehensive Income, Before Tax		3,022		2,316
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost		10		0		87
Interest Cost		206		163		190
Expected Return on Plan Assets		0		0		0
Amortization of Prior Service (Credit) Cost		72		79		53
Amortization of Net Loss		93		139		156
Net Periodic Benefit Cost		381		381		486
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate		4.26%		4.85%
Rate of Compensation Increase		3.50%		3.50%
Interest Rate to Convert Annuities to Actuarially Equivalent Lump Sum Account		4.75%		5.25%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount Rate		4.85%		3.15%		4.05%
Rate of Compensation Increase		3.50%		3.50%		3.50%
Interest Rate to Convert Accuities to Actuarially Equivalent Lump Sum Amounts		5.25%		4.50%		5.00%
Fair Value of Plan Assets		0		0		0
Expected Future Benefit Payments [Abstract]
2015		438
2016		429
2017		419
2018		409
2019		399
2020 - 2024		1,826
Estimated Contributions During 2015	438
Select Executive Retirement Plan [Member] | Scenario, Forecast [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net Actuarial Loss	121
Prior Service (Credit) Cost	58
Postretirement Benefit Plans [Member]
Defined Benefit Plan, Funded Status of Plan [Abstract]
Fair Value of Plan Assets		0		0		0
Benefit Obligation		9,170		7,619		9,213
Funded Status of Plan		-9,170		-7,619
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation, Beginning of Period	9,170	7,619		9,213
Service Cost		173		211		202
Interest Cost		374		308		338
Plan Participants' Contributions		383		368
Amendments		570		0
Actuarial Loss		884		-1,648
Benefits Paid		-833		-833
Benefit Obligation, End of Period		9,170		7,619		9,213
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets, Beginning of Period	0	0		0
Actual Return on Plan Assets		0		0
Contributions to Pension Plans		450		465
Plan Participants' Contributions		383		368
Benefits Paid		-833		-833
Fair Value of Plan Assets, End of Period		0		0		0
Accumulated Benefit Obligation at December 31, 2012		9,170
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Prepaid Benefit Cost		0		0
Accrued Benefit Liability		-9,170		-7,619
Net Benefit Cost Recognized		-9,170		-7,619
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net Retirement Plan Loss, Before-Tax Amount		884		-1,648		491
Net prior Service Cost Arising During the Period		570		0		0
Amortization of Net Loss		-25		-142		-134
Accretion of Net Retirement Plan Prior Service Credit, Tax (Expense) Benefit		114		114		114
Total Other Comprehensive (Loss) Income for Pension and Other Postretirement Benefit Plans		1,543		-1,676		471
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Net Actuarial Loss		1,919		1,060
Prior Service (Credit) Cost		379		-305
Total Accumulated Other Comprehensive Income, Before Tax		2,298		755
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost		173		211		202
Interest Cost		374		308		338
Expected Return on Plan Assets		0		0		0
Amortization of Prior Service (Credit) Cost		-114		-114		-114
Amortization of Net Loss		25		142		134
Net Periodic Benefit Cost		458		547		560
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount Rate		4.31%		5.10%
Rate of Compensation Increase		3.50%		3.50%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount Rate		5.10%		3.55%		4.05%
Rate of Compensation Increase		3.50%		3.50%		3.50%
Fair Value of Plan Assets		0		0		0
Expected Future Benefit Payments [Abstract]
2015		536
2016		554
2017		565
2018		584
2019		615
2020 - 2024		3,323
Estimated Contributions During 2015	536
Postretirement Benefit Plans [Member] | Scenario, Forecast [Member]
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]
Net Actuarial Loss	95
Prior Service (Credit) Cost	($31)
[1]	Acquisition of Arrow Financial Corporation common stock was under 10% of the total fair value of the employee's pension plan assets at the time of acquisition.
[2]	The North Country Funds - Equity and the North Country Funds - Fixed Income are publicly traded mutual funds advised by Arrow's subsidiary, North Country Investment Advisers, Inc.

Other_Expenses_Details

Other Expenses (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Income and Expenses [Abstract]
Computer Services	$3,659	$3,261	$2,263
Legal and Other Professional Fees	1,836	1,823	1,962
Postage and Courier	1,084	1,046	1,040
Stationery and Printing	851	905	975
Advertising and Promotion	886	879	831
Telephone and Communications	746	804	808
Intangible Asset Amortization	387	452	518
All Other	3,531	3,486	3,243
Total Other Operating Expense	$12,980	$12,656	$11,640

Income_Taxes_Current_Income_Ta

Income Taxes Current Income Tax Expense (Benefit), Continuing Operations(Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Tax Expense: Federal	$9,270	$7,933	$8,763
Current Tax Expense: State	1,203	852	1,251
Total Current Tax Expense	10,473	8,785	10,014
Deferred Tax Expense: Federal	-315	172	-290
Deferred Tax Expense: State	16	122	-63
Total Deferred Tax Expense (Benefit)	-299	294	-353
Income Tax Expense (Benefit), Continuing Operations	$10,174	$9,079	$9,661

Income_Taxes_Effective_Income_

Income Taxes Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Computed Tax Expense at Statutory Rate	$11,737	$10,806	$11,144
Tax-Exempt Income	-2,215	-2,238	-2,132
Nondeductible Interest Expense	51	80	95
State Taxes, Net of Federal Income Tax Benefit	791	633	814
Other Items, Net	-190	-202	-260
Income Tax Expense (Benefit), Continuing Operations	$10,174	$9,079	$9,661

Income_Taxes_Components_of_Def

Income Taxes Components of Deferred Tax Assets and Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Tax Assets, Gross [Abstract]
Allowance for Loan Losses	$6,113	$5,794
Pension and Deferred Compensation Plans	3,885	3,999
Pension Liability Included in Accumulated Other Comprehensive Income	6,263	4,426
Other	614	566
Total Gross Deferred Tax Assets	16,875	14,785
Valuation Allowance for Deferred Tax Assets	0	0
Total Gross Deferred Tax Assets, Net of Valuation Allowance	16,875	14,785
Deferred Tax Liabilities, Gross [Abstract]
Pension Plans	7,604	7,724
Depreciation	1,222	1,561
Deferred Income	3,927	3,526
Net Unrealized Gains on Securities Available-for-Sale Included in Accumulated Other Comprehensive Income	1,638	1,557
Goodwill	5,242	5,230
Total Gross Deferred Tax Liabilites	$19,633	$19,598

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Earnings Per Share [Abstract]
Net Income	$23,360	$21,795		$22,179
Basic Shares, in Shares	12,604	12,542	[1]	12,492	[1]
Basic Earnings, in Earnings Per Share	$1.85	$1.74	[1]	$1.78	[1]
Dilutive Average Shares Attributable to Stock Options, in Shares	29	31		10
Weighted Average Shares - Diluted, in Shares	12,633	12,573	[1]	12,502	[1]
Diluted Earnings, In Earnings Per Share	$1.85	$1.73	[1]	$1.77	[1]
Antidilutive Shares Excluded from the Calculation of Earnings Per Share, in Shares	0	47		203
[1]	Share and Per Share Amounts have been restated for the September 2014 2% stock dividend.

Fair_Values_Fair_Value_Recurri

Fair Values Fair Value - Recurring and Nonrecurring (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$366,139	$457,606
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	366,139	457,606
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	366,139	457,606
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	574
Other Real Estate and Repossessed Assets, Net	393	144
Fair Value, Measurements, Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	0
Other Real Estate and Repossessed Assets, Net	0	0
Fair Value, Measurements, Nonrecurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	0
Other Real Estate and Repossessed Assets, Net	0	0
Fair Value, Measurements, Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	574
Other Real Estate and Repossessed Assets, Net	393	144
Fair Value, Measurements, Nonrecurring [Member] | Total Gains (Losses) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral Dependent Impaired Loans	-109
Other Real Estate and Repossessed Assets, Net	-15	-79
U.S. Agency Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	137,603	136,475
U.S. Agency Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
U.S. Agency Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	137,603	136,475
U.S. Agency Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
State and Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	81,730	127,389
State and Municipal Obligations [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	81,730	127,389
State and Municipal Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
State and Municipal Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	81,730	127,389
State and Municipal Obligations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage-Backed Securities - Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	128,827	175,778
Mortgage-Backed Securities - Residential [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	128,827	175,778
Mortgage-Backed Securities - Residential [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mortgage-Backed Securities - Residential [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	128,827	175,778
Mortgage-Backed Securities - Residential [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Corporate and Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,725	16,798
Corporate and Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,725	16,798
Corporate and Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Corporate and Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	16,725	16,798
Corporate and Other Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mututal Funds and Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,254	1,166
Mututal Funds and Equity Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,254	1,166
Mututal Funds and Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0	0
Mututal Funds and Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	1,254	1,166
Mututal Funds and Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$0	$0

Fair_Values_Fair_Value_By_Bala

Fair Values Fair Value By Balance Sheet Grouping (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents	$46,295	$49,980	$48,832	$43,736
Available-for-sale Securities	366,139	457,606
Held-to-Maturity Securities	302,024	299,261
Held-to-maturity Securities, at Fair Value	308,566	302,305
Federal Home Loan Bank and Federal Reserve Bank Stock	4,851	6,281
Net Loans	1,397,698	1,252,038
Deposits	1,902,948	1,842,330
Federal Home Loan Bank Term Advances	10,000	20,000
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	20,000	20,000
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents	46,295	49,980
Available-for-sale Securities	366,139	457,606
Held-to-Maturity Securities	302,024	299,261
Federal Home Loan Bank and Federal Reserve Bank Stock	4,851	6,281
Net Loans	1,397,698	1,252,038
Accrued Interest Receivable	5,834	5,745
Deposits	1,902,948	1,842,330
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase	19,421	11,777
Federal Home Loan Bank Term Advances	51,000	73,000
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	20,000	20,000
Accrued Interest Payable	274	439
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	46,295	49,980
Available-for-sale Securities	366,139	457,606
Held-to-maturity Securities, at Fair Value	308,566	302,305
Federal Home Loan Bank Stock and Federal Reserve Bank Stock, Fair Value Disclosure	4,851	6,281
Net Loans, Fair Value Disclosure	1,405,454	1,266,020
Accrued Interest Receivable, Fair Value Disclosure	5,834	5,745
Deposits, Fair Value Disclosure	1,899,682	1,839,613
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase, Fair Value Disclosure	19,421	11,777
Federal Home Loan Bank Term Advances, Fair Value Disclosure	51,258	74,629
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts, Fair Value Disclosure	20,000	20,000
Accrued Interest Payable, Fair Value Disclosure	274	439
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	46,295	49,980
Available-for-sale Securities	0	0
Held-to-maturity Securities, at Fair Value	0	0
Federal Home Loan Bank Stock and Federal Reserve Bank Stock, Fair Value Disclosure	4,851	6,281
Net Loans, Fair Value Disclosure	0	0
Accrued Interest Receivable, Fair Value Disclosure	5,834	5,745
Deposits, Fair Value Disclosure	1,697,105	1,595,103
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase, Fair Value Disclosure	19,421	11,777
Federal Home Loan Bank Term Advances, Fair Value Disclosure	41,000	53,000
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts, Fair Value Disclosure	0	0
Accrued Interest Payable, Fair Value Disclosure	274	439
Significant Other Observable Inputs (Level 2) [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Available-for-sale Securities	366,139	457,606
Held-to-maturity Securities, at Fair Value	308,566	302,305
Federal Home Loan Bank Stock and Federal Reserve Bank Stock, Fair Value Disclosure	0	0
Net Loans, Fair Value Disclosure	0	0
Accrued Interest Receivable, Fair Value Disclosure	0	0
Deposits, Fair Value Disclosure	202,577	244,510
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase, Fair Value Disclosure	0	0
Federal Home Loan Bank Term Advances, Fair Value Disclosure	10,258	21,629
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts, Fair Value Disclosure	20,000	20,000
Accrued Interest Payable, Fair Value Disclosure	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Available-for-sale Securities	0	0
Held-to-maturity Securities, at Fair Value	0	0
Federal Home Loan Bank Stock and Federal Reserve Bank Stock, Fair Value Disclosure	0	0
Net Loans, Fair Value Disclosure	1,405,454	1,266,020
Accrued Interest Receivable, Fair Value Disclosure	0	0
Deposits, Fair Value Disclosure	0	0
Federal Funds Purchased and Securities Sold Under Agreements to Repurchase, Fair Value Disclosure	0	0
Federal Home Loan Bank Term Advances, Fair Value Disclosure	0	0
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts, Fair Value Disclosure	0	0
Accrued Interest Payable, Fair Value Disclosure	$0	$0

Leases_Rent_Expense_Details

Leases Rent Expense (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Leases [Abstract]
Rent Expense	$784	$671	$597

Leases_Details

Leases (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	$686
2016	483
2017	389
2018	318
2019	266
Later Years	372
Total Minimum Lease Payments	$2,514

Regulatory_Matters_Details

Regulatory Matters (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Arrow Financial Corporation [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) - Actual Amount	$225,766	$212,360
Total Capital (to Risk Weighted Assets) - Actual Ratio	15.50%	15.80%
Total Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Amount	116,524	107,524
Total Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	8.00%	8.00%
Total Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Amount	145,655	134,405
Total Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	10.00%	10.00%
Tier I Capital (to Risk Weighted Assets) - Actual Amount	210,136	197,906
Tier I Capital (to Risk Weighted Assets) - Actual Ratio	14.50%	14.70%
Tier I Capital (to Risk Weighted Assets) - Minimum Acounts For Capital Adequacy Purposes Amount	57,969	53,852
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	86,953	80,778
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	6.00%	6.00%
Tier I Capital (to Average Assets) - Actual Amount	210,136	197,906
Tier I Capital (to Average Assets) - Actual Ratio	9.40%	9.20%
Tier I Capital (to Average Assets) - Minimum Amounts For Capital Adequacy Purposes Amount	89,420	86,046
Tier I Capital (to Average Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier I Capital (to Average Assets) - Minimum Amounts To Be Well-Capitalized Amount	89,420	86,046
Tier I Capital (to Average Assets) - Minimum Amounts To Be Well-Capitalized Ratio	4.00%	4.00%
Glens Falls National [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) - Actual Amount	183,446	172,720
Total Capital (to Risk Weighted Assets) - Actual Ratio	15.50%	15.40%
Total Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Amount	94,682	89,725
Total Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	8.00%	8.00%
Total Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Amount	118,352	112,156
Total Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	10.00%	10.00%
Tier I Capital (to Risk Weighted Assets) - Actual Amount	170,497	160,849
Tier I Capital (to Risk Weighted Assets) - Actual Ratio	14.40%	14.40%
Tier I Capital (to Risk Weighted Assets) - Minimum Acounts For Capital Adequacy Purposes Amount	47,360	44,680
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	71,040	67,020
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	6.00%	6.00%
Tier I Capital (to Average Assets) - Actual Amount	170,497	160,849
Tier I Capital (to Average Assets) - Actual Ratio	9.10%	8.80%
Tier I Capital (to Average Assets) - Minimum Amounts For Capital Adequacy Purposes Amount	74,944	73,113
Tier I Capital (to Average Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier I Capital (to Average Assets) - Minimum Amounts To Be Well-Capitalized Amount	93,680	91,391
Tier I Capital (to Average Assets) - Minimum Amounts To Be Well-Capitalized Ratio	5.00%	5.00%
Saratoga National [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets) - Actual Amount	35,217	33,396
Total Capital (to Risk Weighted Assets) - Actual Ratio	13.30%	14.80%
Total Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Amount	21,183	18,052
Total Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	8.00%	8.00%
Total Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Amount	26,479	22,565
Total Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	10.00%	10.00%
Tier I Capital (to Risk Weighted Assets) - Actual Amount	32,596	30,833
Tier I Capital (to Risk Weighted Assets) - Actual Ratio	12.30%	13.70%
Tier I Capital (to Risk Weighted Assets) - Minimum Acounts For Capital Adequacy Purposes Amount	10,600	9,002
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	15,900	13,504
Tier I Capital (to Risk Weighted Assets) - Minimum Amounts To Be Well-Capitalized Ratio	6.00%	6.00%
Tier I Capital (to Average Assets) - Actual Amount	32,596	30,833
Tier I Capital (to Average Assets) - Actual Ratio	9.40%	9.70%
Tier I Capital (to Average Assets) - Minimum Amounts For Capital Adequacy Purposes Amount	13,871	12,715
Tier I Capital (to Average Assets) - Minimum Amounts For Capital Adequacy Purposes Ratio	4.00%	4.00%
Tier I Capital (to Average Assets) - Minimum Amounts To Be Well-Capitalized Amount	$17,338	$15,893
Tier I Capital (to Average Assets) - Minimum Amounts To Be Well-Capitalized Ratio	5.00%	5.00%

Regulatory_Matters_Other_Regul

Regulatory Matters Other Regulation Disclosures (Details) (USD $)	Dec. 31, 2014
Banking and Thrift [Abstract]
Maximum Subsidiary Dividend	$29,200

Parent_Only_Financial_Informat2

Parent Only Financial Information Parent Only Balance Sheet (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
ASSETS
Interest-Bearing Deposits at Banks	$11,214	$12,705
Available-for-sale Securities	366,139	457,606
Held-to-Maturity Securities	302,024	299,261
Other Assets	46,297	43,235
Total Assets	2,217,420	2,163,698
LIABILITIES
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	20,000	20,000
Other Liabilities	23,125	24,437
Total Liabilities	2,016,494	1,971,544
Equity [Abstract]
Stockholders' Equity Attributable to Parent	200,926	192,154	175,825	166,385
Total Liabilities and Stockholders' Equity	2,217,420	2,163,698
Arrow Financial Corporation [Member]
ASSETS
Interest-Bearing Deposits at Banks	3,013	3,349
Available-for-sale Securities	1,254	1,166
Held-to-Maturity Securities	1,000	1,000
Equity Method Investments	214,813	206,680
Other Assets	6,538	5,807
Total Assets	226,618	218,002
LIABILITIES
Junior Subordinated Obligations Issued to Unconsolidated Subsidiary Trusts	20,000	20,000
Other Liabilities	5,692	5,848
Total Liabilities	25,692	25,848
Equity [Abstract]
Stockholders' Equity Attributable to Parent	200,926	192,154
Total Liabilities and Stockholders' Equity	$226,618	$218,002

Parent_Only_Financial_Informat3

Parent Only Financial Information Parent Only Income Statement (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Interest and Dividends on Investments	$66,861	$64,138	$69,379
Other Operating Income	1,238	1,024	1,170
Net Gains on Securities Transactions	110	540	865
Interest Expense	5,767	7,922	11,957
Salaries and Employee Benefits	30,941	31,182	31,703
Other Operating Expense	12,980	12,656	11,640
Income Tax Benefit	-10,174	-9,079	-9,661
Net Income	23,360	21,795	22,179
Arrow Financial Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from Bank Subsidiaries	13,300	12,900	12,700
Interest and Dividends on Investments	116	116	123
Other Operating Income	578	549	776
Net Gains on Securities Transactions	0	0	63
Total Income	13,994	13,565	13,662
Interest Expense	620	640	692
Salaries and Employee Benefits	77	59	75
Other Operating Expense	754	860	957
Total Expense	1,451	1,559	1,724
Income Before Income Tax Benefit and Equity in Undistributed Net Income of Subsidiaries	12,543	12,006	11,938
Income Tax Benefit	-473	-634	-575
Equity in Undistributed Net Income of Subsidiaries	10,344	9,155	9,666
Net Income	$23,360	$21,795	$22,179

Parent_Only_Financial_Informat4

Parent Only Financial Information Parent Only Statement of Cash Flows (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Cash Flows from Operating Activities:
Net Income	$23,360,000		$21,795,000		$22,179,000
Gains on the Sale of Securities Available-for-Sale	137,000		527,000		949,000
Stock-Based Compensation Expense	360,000		372,000		424,000
Stock-Based Compensation Expense	360,000		372,000		424,000
Net Cash Provided By Operating Activities	30,641,000		36,673,000		32,460,000
Cash Flows from Investing Activities:
Proceeds from the Sale of Securities Available-for-Sale	49,928,000		16,295,000		58,718,000
Purchases of Securities Available-for-Sale	-113,953,000		-136,416,000		-197,029,000
Net Cash Used In Investing Activities	-67,693,000		-149,015,000		-65,645,000
Cash Flows from Financing Activities:
Stock Options Exercised	1,454,000		1,254,000		2,105,000
Shares Issued Under the Employee Stock Purchase Plan	488,000		477,000		484,000
Shares Issued for Dividend Reinvestment Plans			-1,280,000		-1,822,000
Tax Benefit from Exercise of Stock Options	25,000		23,000		68,000
Purchases of Treasury Stock	2,455,000		1,709,000		4,877,000
Cash Dividends Paid	-12,407,000	[1]	-12,109,000	[1]	-11,815,000	[1]
Net Cash Provided By Financing Activities	33,367,000		113,490,000		38,281,000
Net Increase (Decrease) in Cash and Cash Equivalents	-3,685,000		1,148,000		5,096,000
Cash and Cash Equivalents at Beginning of Year	49,980,000		48,832,000		43,736,000
Cash and Cash Equivalents at End of Year	46,295,000		49,980,000		48,832,000
Interest on Deposits and Borrowings	5,932,000		8,067,000		12,520,000
Shares Issued for Acquisition of Subsidiary	91,000		233,000		233,000
Arrow Financial Corporation [Member]
Cash Flows from Operating Activities:
Net Income	23,360,000		21,795,000		22,179,000
Undistributed Net Income of Subsidiaries	-10,344,000		-9,155,000		-9,666,000
Gains on the Sale of Securities Available-for-Sale	0		0		-63,000
Stock-Based Compensation Expense	197,000		198,000		175,000
Stock-Based Compensation Expense	360,000		372,000		424,000
Changes in Other Assets and Other Liabilities	-1,014,000		-990,000		-1,640,000
Net Cash Provided By Operating Activities	12,559,000		12,220,000		11,409,000
Cash Flows from Investing Activities:
Proceeds from the Sale of Securities Available-for-Sale	45,000		45,000		681,000
Purchases of Securities Available-for-Sale	-45,000		-45,000		-359,000
Net Cash Used In Investing Activities	0		0		322,000
Cash Flows from Financing Activities:
Stock Options Exercised	1,942,000		1,254,000		2,105,000
Shares Issued Under the Employee Stock Purchase Plan	0		477,000		484,000
Shares Issued for Dividend Reinvestment Plans	0		1,280,000		1,822,000
Tax Benefit from Exercise of Stock Options	25,000		23,000		68,000
Purchases of Treasury Stock	-2,455,000		-1,709,000		-4,877,000
Cash Dividends Paid	-12,407,000		-12,109,000		-11,815,000
Net Cash Provided By Financing Activities	-12,895,000		-10,784,000		-12,213,000
Net Increase (Decrease) in Cash and Cash Equivalents	-336,000		1,436,000		-482,000
Cash and Cash Equivalents at Beginning of Year	3,349,000		1,913,000		2,395,000
Cash and Cash Equivalents at End of Year	3,013,000		3,349,000		1,913,000
Interest on Deposits and Borrowings	620,000		640,000		692,000
Shares Issued for Acquisition of Subsidiary	$91,000		$233,000		$233,000
[1]	Cash dividends paid per share have been adjusted for the September 2014 2% stock dividend.