EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2011

EMPLOYEE BENEFIT PLANS

Summary of Company's target asset allocation percentages for major categories of the pension plan

	Minimum Exposure			Target			Maximum Exposure
Fixed Income		35	%		40	%		45	%
Total Domestic Equity		40	%		50	%		60	%
Small Cap Stocks		10	%		15	%		20	%
Large Cap Stocks		30	%		35	%		45	%
Non-U.S. Equities		5	%		10	%		15	%

Schedule of fair value plan assets

	Pension Benefits										Other Benefits
	2011		%			2010		%			2011		%			2010		%
Fixed Income	$	79,859		51	%	$	60,961		44	%	$	16,006		59	%	$	11,184		53	%
Domestic Equity
Small Cap Stocks		27,262					27,580					—					—
Large Cap Stocks		40,689					41,583					10,972					9,986
Total Domestic Equity		67,951		44	%		69,163		50	%		10,972		41	%		9,986		47	%
Non U.S. Equities		7,939		5	%		8,910		6	%		—		0	%		—		0	%
Total Plan Assets	$	155,749		100	%	$	139,034		100	%	$	26,978		100	%	$	21,170		100	%

Schedule of reconciliation of the funded status of the plans with the accrued pension liability and the net postretirement benefit liability

	Pension Benefits						Other Benefits
	2011			2010			2011			2010
Change in projected benefit obligation:
Beginning of year	$	269,940		$	219,730		$	45,944		$	39,353
Service cost		11,713			10,076			3,199			2,491
Interest cost		14,683			13,701			2,872			2,329
Assumption change		59,028			23,820			12,600			5,524
Experience (gain) loss		(6,030	)		5,364			5,705			(2,423	)
Benefits paid, net of retiree premiums		(3,029	)		(2,751	)		(1,213	)		(1,330	)
End of year	$	346,305		$	269,940		$	69,107		$	45,944
Change in plan assets:
Fair value of plan assets at beginning of year	$	139,034		$	105,639		$	21,178		$	15,864
Actual return on plan assets		555			13,893			64			1,204
Employer contributions		19,189			22,253			6,949			5,440
Retiree contributions and Medicare part D subsidies		—			—			1,130			1,139
Benefits paid		(3,029	)		(2,751	)		(2,343	)		(2,469	)
Fair value of plan assets at end of year	$	155,749		$	139,034		$	26,978		$	21,178
Funded status	$	(190,556	)	$	(130,906	)	$	(42,129	)	$	(24,766	)
Unrecognized actuarial loss		123,177			65,853			34,515			16,102
Unrecognized prior service cost		47,976			54,296			537			653
Unrecognized transition obligation		—			—			285			561
Net amount recognized	$	(19,403	)	$	(10,757	)	$	(6,792	)	$	(7,450	)

Schedule of amounts recognized in consolidated balance sheets

	Pension Benefits						Other Benefits
	2011			2010			2011			2010
Prepaid (Accrued) benefit costs	$	—		$	—		$	(6,792	)	$	(7,450	)
Accrued benefit liability		(190,556	)		(130,906	)		(35,337	)		(17,316	)
Regulatory asset		171,153			120,149			35,337			17,316
Net amount recognized	$	(19,403	)	$	(10,757	)	$	(6,792	)	$	(7,450	)

Schedule of actuarial assumptions used in determining the benefit obligation

	Pension Benefits						Other Benefits
	2011			2010			2011			2010
Weighted average assumptions as of December 31:
Discount rate		4.40	%		5.60	%		4.50	%		5.60	%
Long-term rate of return on plan assets		7.00	%		6.75	%		6.25	%		6.00	%
Rate of compensation increases		3.50	%		4.00	%		—			—
Cost of living adjustment		3.00	%		3.00	%		—			—

Components of the pension plans and other postretirement benefits

	Pension Plan									Other Benefits
	2011			2010			2009			2011			2010			2009
Service cost	$	11,713		$	10,076		$	9,119		$	3,199		$	2,491		$	2,261
Interest cost		14,683			13,701			12,352			2,872			2,329			2,161
Expected return on plan assets		(8,949	)		(8,228	)		(7,155	)		(1,372	)		(1,119	)		(785	)
Net amortization and deferral		10,387			9,224			8,063			1,592			1,081			1,289
Net periodic benefit cost	$	27,834		$	24,773		$	22,379		$	6,291		$	4,782		$	4,926

Schedule of actuarial assumptions used in determining the net periodic benefit costs

	Pension Benefits						Other Benefits
	2011			2010			2011			2010
Weighted average assumptions as of December 31:
Discount rate		5.60	%		6.10	%		5.60	%		6.00	%
Long-term rate of return on plan assets		6.75	%		7.50	%		6.00	%		6.50	%
Rate of compensation increases		4.00	%		4.00	%		—			—

Schedule of the effect of a one-percentage point change in assumed health care cost trends

	1-Percentage Point Increase		1-Percentage Point Decrease
Effect on total service and interest costs	$	1,467	$	(1,110	)
Effect on accumulated postretirement benefit obligation	$	14,841	$	(11,390	)