RETIREMENT BENEFITS (Tables)

12 Months Ended

Dec. 31, 2011

Retirement benefits

Schedule of the Company's benefit plans' projected benefit obligations

	Pension						SERP						OPEB
	2011			2010			2011			2010			2011			2010
Benefit obligation at beginning of year	$	186,840		$	169,055		$	2,895		$	2,575		$	80,938		$	69,911
Service cost		5,596			4,887			93			70			2,266			2,138
Interest cost		10,405			10,115			183			153			4,383			4,329
Net actuarial (gain)/loss		20,869			10,946			1,883			160			(2,136	)		6,454
Plan participant's contribution		—			—			—			—			863			949
Benefits and expenses paid		(8,622	)		(8,163	)		(191	)		(63	)		(3,261	)		(2,966	)
Federal subsidy		—			—			—			—			173			123
Benefit obligation at end of year	$	215,088		$	186,840		$	4,863		$	2,895		$	83,226		$	80,938

Schedule of fair value of the plans' assets

	Pension						SERP				OPEB
	2011			2010			2011		2010		2011			2010
Fair value of plan assets at beginning of year	$	120,353		$	107,076		$	—	$	—	$	56,730		$	50,036
Actual return on plan assets — gain/(loss)		(625	)		11,740			—		—		279			4,825
Employer contribution		29,869			9,700			—		—		3,544			3,681
Benefits paid		(8,622	)		(8,163	)		—		—		(3,160	)		(2,845	)
Plan participant's contribution		—			—			—		—		826			917
Federal subsidy		—			—			—		—		165			116
Fair value of plan assets at end of year	$	140,975		$	120,353		$	—	$	—	$	58,384		$	56,730

Schedule of the funded status

	Pension						SERP						OPEB
	2011			2010			2011			2010			2011			2010
Fair value of plan assets	$	140,975		$	120,353		$	—		$	—		$	58,384		$	56,730
Projected benefit obligations		(215,088	)		(186,840	)		(4,863	)		(2,895	)		(83,226	)		(80,938	)
Funded status	$	(74,113	)	$	(66,487	)	$	(4,863	)	$	(2,895	)	$	(24,842	)	$	(24,208	)

Schedule of amounts recognized in the balance sheet

	Pension				SERP				OPEB
	2011		2010		2011		2010		2011		2010
Accounts Payable and Accrued Liabilities	$	—	$	—	$	311	$	64	$	136	$	121
Pension and other postretirement benefit obligation	$	74,113	$	66,487	$	4,552	$	2,831	$	24,706	$	24,087

Schedule of employee pension plan accumulated benefit obligation

	Pension Benefits				SERP
	2011		2010		2011		2010
Accumulated benefit obligation	$	191,295	$	164,340	$	4,670	$	2,431

Schedule of net periodic benefit pension cost

	Pension									OPEB
	2011			2010			2009			2011			2010			2009
Service cost	$	5,596		$	4,887		$	4,612		$	2,266		$	2,138		$	1,830
Interest cost		10,405			10,115			9,876			4,383			4,329			3,907
Expected return on plan assets		(11,139	)		(9,847	)		(10,379	)		(4,157	)		(3,844	)		(3,843	)
Amortization of prior service cost(1)		532			531			604			(1,011	)		(1,011	)		(1,011	)
Amortization of actuarial loss(1)		5,494			3,996			3,182			1,762			1,499			869
Net periodic benefit cost	$	10,888		$	9,682		$	7,895		$	3,243		$	3,111		$	1,752

Net Periodic Pension Benefit Cost:

	SERP
	2011			2010			2009
Service cost	$	93		$	70		$	61
Interest cost		183			153			148
Expected return on plan assets		—			—			—
Amortization of prior service cost(1)		(8	)		(8	)		(8	)
Amortization of actuarial loss(1)		171			96			103
Net periodic benefit cost	$	439		$	311		$	304

(1)

Amounts are amortized from our regulatory asset originally recorded upon recognizing our net pension liability on the balance sheet.

Schedule of activity in the regulatory asset accounts

			Amount Recognized
Regulatory Assets	Beginning Balance 12/31/10		Current Year Actuarial Loss		Amortization of Actuarial Loss			Amortization of Prior Service (Cost)/Credit			Ending Balance 12/31/11
Pension	$	67,050		32,632		(5,494	)		(532	)	$	93,656
SERP	$	1,291		1,884		(171	)		8		$	3,012
OPEB	$	16,031		1,740		(1,762	)		1,011		$	17,020

Schedule of net actuarial gains / losses, transition obligations / assets and prior period service costs in regulatory assets not yet recognized as a component of net periodic benefit cost and the amounts expected to be recognized in the subsequent year

	Pension Benefits				SERP						OPEB
	2011		Subsequent Period		2011			Subsequent Period			2011			Subsequent Period
Net actuarial loss	$	91,144	$	7,799	$	3,051		$	305		$	22,637		$	1,871
Prior service cost (benefit)		2,512		532		(39	)		(8	)		(5,617	)		(1,011	)
Total	$	93,656	$	8,331	$	3,012		$	297		$	17,020		$	860

Schedule of assumptions used to determine the benefit obligation

	Pension Benefits						OPEB
	2011			2010			2011			2010
Discount rate		4.70	%		5.50	%		4.90	%		5.50	%
Rate of compensation increase		3.50	%		4.50	%		3.50	%		4.50	%

Schedule of assumptions used to determine the periodic costs

	Pension Benefits									OPEB
	2011			2010			2009			2011			2010			2009
Discount rate		5.50	%		6.00	%		6.30	%		5.50	%		6.00	%		6.30	%
Expected return on plan assets		8.00	%		8.00	%		8.50	%		7.00	%		7.00	%		7.45	%
Rate of compensation increase		4.50	%		4.50	%		4.50	%		4.50	%		4.50	%		4.50	%

Pensions

Retirement benefits

Schedule of expected benefit payments

Year	Payments from Trust		Payments from Company Funds
2012	$	8.4	$	0.3
2013		9.0		0.3
2014		9.7		0.3
2015		10.4		0.3
2016		11.1		0.3
2017 – 2021	$	65.9	$	1.9

Schedule of fund assets measured at fair value

	Fair Value Measurements as of December 31, 2011
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total		Percentage of Plan Assets
Short term investments	$	—	$	1,787	$	—	$	1,787		1.2	%
Equity securities
U.S. equity		57,228		—		—		57,228		40.6	%
International equity		19,151		—		—		19,151		13.6	%
Fixed income
Common collective trust		—		22,904		—		22,904		16.3	%
U.S. corporate debt		—		11,692		—		11,692		8.3	%
U.S. government debt		794		—		—		794		0.6	%
Other types of investments
Equity long/short hedge funds		—		—		27,419		27,419		19.4	%
	$	77,173	$	36,383	$	27,419	$	140,975		100.0	%

	Fair Value Measurements as of December 31, 2010
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total		Percentage of Plan Assets
Short term investments	$	—	$	1,387	$	—	$	1,387		1.1	%
Equity securities
U.S. equity		47,797		—		—		47,797		39.7	%
International equity		15,876		—		—		15,876		13.2	%
Fixed income
Common collective trust		—		32,955		—		32,955		27.4	%
Other types of investments
Equity long/short hedge funds		—		—		22,338		22,338		18.6	%
	$	63,673	$	34,342	$	22,338	$	120,353		100.0	%

Schedule of fair value measurements using significant unobservable inputs (level 3)

	2011			2010
	Equity long/short hedge funds			Equity long/short hedge funds
Beginning Balance, January 1,	$	22,338		$	23,515
Actual return on plan assets:
Relating to assets still held at the reporting date		(669	)		1,423
Relating to assets sold during the period		—			—
Purchases		5,750			—
Sales		—			(2,600	)
Settlements					—
Transfers into and (out of) Level 3		—			—
Ending Balance, December 31,	$	27,419		$	22,338

Schedule of permissible investments

Equity Oriented		Fixed Income Oriented and Real Estate
•	Common Stocks	•	Bonds
•	Preferred Stocks	•	GICs, BICs
•	Convertible Preferred Stocks	•	Corporate Bonds (minimum quality rating
•	Convertible Bonds		of Baa or BBB)
•	Covered Options	•	Cash-Equivalent Securities (e.g., U.S.
•	Hedged Equity Funds of Funds		T-Bills, Commercial Paper, etc.)
	protection	•	Certificates of Deposit in institutions with FDIC/FSLIC
		•	Money Market Funds / Bank STIF Funds
		•	Real Estate — Publicly Traded

        The above assets can be held in commingled (mutual) funds as well as privately managed separate accounts.

        Those investments prohibited by the Investment Committee without prior approval are:

Prohibited Investments Requiring Pre-approval

•	Privately Placed Securities	•	Warrants
•	Commodities Futures	•	Short Sales
•	Securities of Empire District	•	Index Options
•	Derivatives

OPEB

Retirement benefits

Schedule of expected benefit payments

Year	Payments from Trust		Expected Federal Subsidy		Payments from Company Funds
2012	$	2.3	$	0.3	$	0.1
2013		2.6		0.3		0.1
2014		2.9		0.4		0.1
2015		3.1		0.4		0.1
2016		3.5		0.5		0.2
2017 – 2021	$	21.3	$	3.1	$	0.9

Schedule of effect of 1% change in assumed healthcare cost growth rates

	1% Increase		1% Decrease
Effect on total of service and interest cost	$	1,258	$	(990	)
Effect on post-retirement benefit obligation	$	12,663	$	(10,235	)

Schedule of fund assets measured at fair value

	Fair Value Measurements as of December 31, 2011
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total		Percentage of Plan Assets
Cash and cash equivalents	$	1,536	$	—	$	—	$	1,536		2.6	%
Fixed income
U.S. government debt		—		1,839		—		1,839		3.1	%
U.S. corporate debt		—		17,232		—		17,232		29.5	%
Foreign debt		—		1,460		—		1,460		2.5	%
Mutual funds — fixed income		2,107		—		—		2,107		3.6	%
Equity securities
U.S. equity		21,080		—		—		21,080		36.1	%
International equity		1,784		—		—		1,784		3.1	%
Mutual funds — equity		11,075		—		—		11,075		19.0	%
		37,582		20,531		—		58,113
Accrued interest & dividends								271		0.5	%
							$	58,384		100	%

	Fair Value Measurements as of December 31, 2010
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total		Percentage of Plan Assets
Cash and cash equivalents	$	3,897	$	—	$	—	$	3,897		7.0	%
Fixed income
U.S. government debt		—		4,091		—		4,091		7.2	%
U.S. corporate debt		—		15,156		—		15,156		26.7	%
Foreign debt		—		420		—		420		0.7	%
Mutual funds — fixed income		1,496		—		—		1,496		2.6	%
Equity securities
U.S. equity		17,592		—		—		17,592		31.0	%
International equity		1,274		—		—		1,274		2.2	%
Mutual funds — equity		12,556		—		—		12,556		22.1	%
		36,815		19,667		—		56,482
Accrued interest & dividends								248		0.5	%
							$	56,730		100	%

Schedule of permissible investments

Equity		Fixed Income
•	Common Stocks	•	Cash-Equivalent Securities with a maturity
•	Preferred Stocks		of one-year or less
		•	Bonds
		•	Money Market Funds / Bank STIF Funds
		•	Certificates of Deposit in institutions with FDIC protection
		•	Corporate Bonds (minimum quality rating of A)

        The above assets can be held in commingled (mutual) funds as well as privately managed separate accounts.

        Listed below are those investments prohibited by the Investment Committee:

Prohibited Investments

•	Privately Placed Securities	•	Margin Transactions
•	Commodities Futures	•	Short Sales
•	Securities of Empire District	•	Index Options
•	Derivatives	•	Real Estate and Real Property
•	Instrumentalities in violation of the Prohibited Transactions Standards of ERISA	•	Restricted Stock