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' Pension Plan			Select Executive Retirement Plan			Postretirement Benefit Plans
Defined Benefit Plan Funded Status
December 31, 2014
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	)
December 31, 2013
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' Pension Plan			Select Executive Retirement Plan			Postretirement Benefit Plans
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
December 31, 2014
Prepaid Pension Asset	$	8,738		$	—		—
Accrued Benefit Liability	—			(5,072		)	(9,170		)
Net Benefit Recognized	$	8,738		$	(5,072	)	$	(9,170	)
December 31, 2013
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      Other Postretirement Benefit Plans	$	2,544		$	706		$	1,543
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      Other Postretirement Benefit Plans	$	(9,706	)	$	(773	)	$	(1,676	)

Schedule of Defined Benefit Plan Disclosures
	Employees' Pension Plan			Select Executive Retirement Plan			Postretirement Benefit Plans
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      Other Postretirement Benefit Plans	$	(142	)	$	637		$	471
Accumulated Other Comprehensive Income
December 31, 2014
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
December 31, 2013
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
December 31, 2014
Discount Rate	4.31		%	4.26		%	4.31		%
Rate of Compensation Increase	3.50		%	3.50		%	3.50		%

Schedule of Defined Benefit Plan Disclosures
	Employees' Pension Plan		Select Executive Retirement Plan		Postretirement Benefit Plans
Interest Rate Credit for Determining   Projected Cash Balance Account	3.04	%
Interest Rate to Annuitize Cash       Balance Account	4.75	%
Interest Rate to Convert Annuities to Actuarially   Equivalent Lump Sum Amounts	4.75	%	4.75	%
December 31, 2013
Discount Rate	5.10	%	4.85	%	5.10	%
Rate of Compensation Increase	3.50	%	3.50	%	3.50	%
Interest Rate Credit for Determining   Projected Cash Balance Account	4.00	%
Interest Rate to Annuitize Cash       Balance Account	5.25	%
Interest Rate to Convert Annuities to Actuarially   Equivalent Lump Sum Amounts	5.25	%	5.25	%
Weighted-Average Assumptions Used in   Calculating Net Periodic Benefit Cost
December 31, 2014
Discount Rate	5.10	%	4.85	%	5.10	%
Expected Long-Term Return on Plan Assets	7.50	%
Rate of Compensation Increase	3.50	%	3.50	%	3.50	%
Interest Rate Credit for Determining       Projected Cash Balance Account	4.00	%
Interest Rate to Annuitize Cash       Balance Account	5.25	%
Interest Rate to Convert Annuities to Actuarially   Equivalent Lump Sum Amounts	5.25	%	5.25	%
December 31, 2013
Discount Rate	3.55	%	3.15	%	3.55	%
Expected Long-Term Return on Plan Assets	7.50	%
Rate of Compensation Increase	3.50	%	3.50	%	3.50	%
Interest Rate Credit for Determining       Projected Cash Balance Account	3.00	%
Interest Rate to Annuitize Cash       Balance Account	4.50	%
Interest Rate to Convert Annuities to Actuarially   Equivalent Lump Sum Amounts	4.50	%	4.50	%
December 31, 2012
Discount Rate	4.05	%	4.05	%	4.05	%
Expected Long-Term Return on Plan Assets	7.50	%
Rate of Compensation Increase	3.50	%	3.50	%	3.50	%
Interest Rate Credit for Determining       Projected Cash Balance Account	3.25	%
Interest Rate to Annuitize Cash       Balance Account	5.00	%
Interest Rate to Convert Annuities to Actuarially   Equivalent Lump Sum Amounts	5.00	%	5.00	%

Schedule of Defined Benefit Plan Disclosures Information about Defined Benefit Plan Assets - Employees' Pension Plan
Fair Value Measurements Using:
Asset Category	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total		Percent of Total		Target Allocation Minimum		Target Allocation Maximum
December 31, 2014
Cash	$	20	$	—	$	—	$	20	—	%	—	%	15.0	%
Interest-Bearing Money Market Fund	4,322		—		—		4,322		9.5	%	—	%	15.0	%
Arrow Common Stock1	4,551		—		—		4,551		10.0	%	—	%	10.0	%
North Country Funds - Equity 2	18,975		—		—		18,975		41.4	%
Other Mutual Funds - Equity	10,954		—		—		10,954		24.0	%
Total Equity Funds	29,929		—		—		29,929		65.4	%	66.0	%	85.0	%
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	%	15.0	%	30.0	%
Total	$	45,704	$	—	$	—	$	45,704	100.0	%
December 31, 2013
Cash	$	7	$	—	$	—	$	7	—	%	—	%	15.0	%
Interest-Bearing Money Market Fund	3,941		—		—		3,941		8.8	%	—	%	15.0	%
Arrow Common Stock1	4,291		—		—		4,291		9.6	%	—	%	10.0	%
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	%	55.0	%	85.0	%
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	%	10.0	%	30.0	%
Total	$	44,653	$	—	$	—	$	44,653	100.0	%