Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

Changes in benefit obligation and plan assets

Changes in benefit obligation and plan assets for the years ended December 31, 2012 and 2011, and amounts recognized in the Consolidated Balance Sheets at December 31, 2012 and 2011, were as follows:

	Pension Benefits						Other Postretirement Benefits
	2012			2011			2012			2011
	(In thousands)
Change in benefit obligation:
Benefit obligation at beginning of year	$	435,618		$	388,589		$	110,689		$	91,286
Service cost	1,078			2,252			1,747			1,443
Interest cost	17,598			19,500			4,166			4,700
Plan participants' contributions	—			—			2,688			2,644
Amendments	—			—			(11,418		)	—
Actuarial loss	30,939			62,722			3,469			17,940
Curtailment gain	—			(13,939		)	—			—
Benefits paid	(26,122		)	(23,506		)	(7,983		)	(7,324		)
Benefit obligation at end of year	459,111			435,618			103,358			110,689
Change in net plan assets:
Fair value of plan assets at beginning of year	278,000			277,598			68,085			70,610
Actual gain (loss) on plan assets	34,493			(4,718		)	6,497			(872		)
Employer contribution	22,813			28,626			5,074			3,027
Plan participants' contributions	—			—			2,688			2,644
Benefits paid	(26,122		)	(23,506		)	(7,983		)	(7,324		)
Fair value of net plan assets at end of year	309,184			278,000			74,361			68,085
Funded status - under	$	(149,927	)	$	(157,618	)	$	(28,997	)	$	(42,604	)
Amounts recognized in the Consolidated Balance Sheets at December 31:
Other accrued liabilities (current)	$	—		$	—		$	(655	)	$	(550	)
Other liabilities (noncurrent)	(149,927		)	(157,618		)	(28,342		)	(42,054		)
Net amount recognized	$	(149,927	)	$	(157,618	)	$	(28,997	)	$	(42,604	)
Amounts recognized in accumulated other comprehensive (income) loss consist of:
Actuarial loss	$	202,406		$	189,494		$	43,589		$	43,861
Prior service cost (credit)	437			(632		)	(18,594		)	(8,615		)
Transition obligation	—			—			—			2,128
Total	$	202,843		$	188,862		$	24,995		$	37,374

The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for the pension plans with accumulated benefit obligations in excess of plan assets

The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for the pension plans, of which all have accumulated benefit obligations in excess of plan assets, at December 31 were as follows:

	2012		2011
	(In thousands)
Projected benefit obligation	$	459,111	$	435,618
Accumulated benefit obligation	$	459,111	$	435,618
Fair value of plan assets	$	309,184	$	278,000

Components of net periodic benefit cost

Components of net periodic benefit cost for the Company's pension and other postretirement benefit plans for the years ended December 31 were as follows:

	Pension Benefits									Other Postretirement Benefits
	2012			2011			2010			2012			2011			2010
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	1,078		$	2,252		$	2,889		$	1,747		$	1,443		$	1,357
Interest cost	17,598			19,500			19,761			4,166			4,700			4,817
Expected return on assets	(23,536		)	(22,809		)	(23,643		)	(4,890		)	(5,051		)	(5,512		)
Amortization of prior service cost (credit)	(46		)	45			152			(1,438		)	(2,677		)	(3,303		)
Recognized net actuarial loss	7,070			4,656			2,622			2,134			753			845
Curtailment loss (gain)	(1,023		)	1,218			—			—			—			—
Amortization of net transition obligation	—			—			—			2,128			2,125			2,125
Net periodic benefit cost, including amount capitalized	1,141			4,862			1,781			3,847			1,293			329
Less amount capitalized	937			1,196			791			910			(50		)	(92		)
Net periodic benefit cost	204			3,666			990			2,937			1,343			421
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive (income) loss:
Net loss	19,982			76,310			20,477			1,863			23,863			1,462
Prior service cost (credit)	—			—			353			(11,418		)	—			121
Amortization of actuarial loss	(7,070		)	(4,656		)	(2,622		)	(2,134		)	(753		)	(845		)
Amortization of prior service (cost) credit	1,069			(1,263		)	(152		)	1,438			2,677			3,303
Amortization of net transition obligation	—			—			—			(2,128		)	(2,125		)	(2,125		)
Total recognized in accumulated other comprehensive (income) loss	13,981			70,391			18,056			(12,379		)	23,662			1,916
Total recognized in net periodic benefit cost and accumulated other comprehensive (income) loss	$	14,185		$	74,057		$	19,046		$	(9,442	)	$	25,005		$	2,337

Weighted average assumptions used to determine benefit obligations and net periodic benefit costs

Weighted average assumptions used to determine benefit obligations at December 31 were as follows:

	Pension Benefits				Other Postretirement Benefits
	2012		2011		2012		2011
Discount rate	3.65	%	4.16	%	3.67	%	4.13	%
Expected return on plan assets	7.00	%	7.75	%	6.00	%	6.75	%
Rate of compensation increase	N/A		N/A		4.00	%	4.00	%

Weighted average assumptions used to determine net periodic benefit cost for the years ended December 31 were as follows:

	Pension Benefits					Other Postretirement Benefits
	2012		2011			2012		2011
Discount rate	4.16	%	5.26	%		4.13	%	5.21	%
Expected return on plan assets	7.75	%	7.75	%		6.75	%	6.75	%
Rate of compensation increase	N/A*		4.00	%	/N/A*	4.00	%	4.00	%

* Effective June 30, 2011 and September 30, 2012, all benefit and service accruals for a union plan were frozen. Compensation increases had previously been frozen for all other plans.

Health care rate assumptions for the Company's other postretirement benefit plans

Health care rate assumptions for the Company's other postretirement benefit plans as of December 31 were as follows:

				2012					2011
Health care trend rate assumed for next year	6.0	%	-	8.0	%	6.0	%	-	8.0	%
Health care cost trend rate - ultimate	5.0	%	-	6.0	%	5.0	%	-	6.0	%
Year in which ultimate trend rate achieved				2017					2017

Assumed health care cost trend rates

Assumed health care cost trend rates may have a significant effect on the amounts reported for the health care plans. A one percentage point change in the assumed health care cost trend rates would have had the following effects at December 31, 2012:

	1 Percentage  Point Increase		1 Percentage Point  Decrease
	(In thousands)
Effect on total of service and interest cost components	$	340	$	(278	)
Effect on postretirement benefit obligation	$	5,724	$	(4,858	)

The fair value of the Company's pension net plan assets by class

The fair value of the Company's pension net plan assets by class is as follows:

	Fair Value Measurements at December 31, 2012, Using
	Quoted Prices in Active Markets for Identical Assets  (Level 1)		Significant Other Observable Inputs  (Level 2)		Significant Unobservable  Inputs  (Level 3)		Balance at December 31, 2012
	(In thousands)
Assets:
Cash equivalents	$	2,145	$	10,460	$	—	$	12,605
Equity securities:
U.S. companies	86,981		—		—		86,981
International companies	39,818		—		—		39,818
Collective and mutual funds*	82,787		20,065		—		102,852
Corporate bonds	—		45,112		—		45,112
Municipal bonds	—		9,302		—		9,302
U.S. Treasury securities	7,980		4,534		—		12,514
Total assets measured at fair value	$	219,711	$	89,473	$	—	$	309,184

* Collective and mutual funds invest approximately 12 percent in common stock of mid-cap U.S. companies, 26 percent in common stock of large-cap U.S. companies, 13 percent in U.S. Treasuries, 41 percent in corporate bonds and 8 percent in other investments.

	Fair Value Measurements at December 31, 2011, Using
	Quoted Prices in Active Markets for Identical Assets  (Level 1)		Significant Other Observable Inputs  (Level 2)		Significant Unobservable  Inputs  (Level 3)		Balance at December 31, 2011
	(In thousands)
Assets:
Cash equivalents	$	2,256	$	17,534	$	—	$	19,790
Equity securities:
U.S. companies	99,315		—		—		99,315
International companies	35,353		—		—		35,353
Collective and mutual funds*	43,214		15,541		—		58,755
Corporate bonds	—		23,579		289		23,868
Mortgage-backed securities	—		22,987		—		22,987
Municipal bonds	—		9,290		—		9,290
U.S. Treasury securities	—		8,642		—		8,642
Total assets measured at fair value	$	180,138	$	97,573	$	289	$	278,000

* Collective and mutual funds invest approximately 26 percent in common stock of mid-cap U.S. companies, 26 percent in common stock of large-cap U.S. companies, 13 percent in U.S. Treasuries, 6 percent in corporate bonds and 29 percent in other investments.

Summary of changes in the fair value of the pension plan's Level 3 assets

The following table sets forth a summary of changes in the fair value of the pension plans' Level 3 assets for the year ended December 31, 2012:

	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Corporate Bonds
	(In thousands)
Balance at beginning of year	$	289
Total realized/unrealized losses	(47		)
Purchases, issuances and settlements (net)	(242		)
Balance at end of year	$	—

The following table sets forth a summary of changes in the fair value of the pension plans' Level 3 assets for the year ended December 31, 2011:

	Fair Value Measurements Using Significant Unobservable Inputs (Level 3)
	Corporate Bonds			Collateral Held on Loaned Securities			Total
	(In thousands)
Balance at beginning of year	$	—		$	694		$	694
Total realized/unrealized losses	(2		)	(259		)	(261		)
Purchases, issuances and settlements (net)	291			(435		)	(144		)
Balance at end of year	$	289		$	—		$	289

Fair value of other postretirement benefit plan assets by asset class

The fair value of the Company's other postretirement benefit plan assets by asset class is as follows:

	Fair Value Measurements at December 31, 2012, Using
	Quoted Prices in Active Markets for Identical Assets  (Level 1)		Significant Other Observable Inputs  (Level 2)		Significant Unobservable  Inputs  (Level 3)		Balance at December 31, 2012
	(In thousands)
Assets:
Cash equivalents	$	1,053	$	1,991	$	—	$	3,044
Equity securities:
U.S. companies	2,207		—		—		2,207
International companies	260		—		—		260
Insurance investment contract*	—		68,850		—		68,850
Total assets measured at fair value	$	3,520	$	70,841	$	—	$	74,361

* The insurance investment contract invests approximately 51 percent in common stock of large-cap U.S. companies, 15 percent in U.S. Treasuries, 10 percent in mortgage-backed securities, 11 percent in corporate bonds and 13 percent in other investments.

	Fair Value Measurements at December 31, 2011, Using
	Quoted Prices in Active Markets for Identical Assets  (Level 1)		Significant Other Observable Inputs  (Level 2)		Significant Unobservable  Inputs  (Level 3)		Balance at December 31, 2011
	(In thousands)
Assets:
Cash equivalents	$	59	$	1,836	$	—	$	1,895
Equity securities:
U.S. companies	2,098		—		—		2,098
International companies	262		—		—		262
Insurance investment contract*	—		63,830		—		63,830
Total assets measured at fair value	$	2,419	$	65,666	$	—	$	68,085

* The insurance investment contract invests approximately 49 percent in common stock of large-cap U.S. companies, 15 percent in U.S. Treasuries, 12 percent in mortgage-backed securities, 11 percent in corporate bonds and 13 percent in other investments.

Benefit payments expected to be paid

The following benefit payments, which reflect future service, as appropriate, and expected Medicare Part D subsidies are as follows:

Years	Pension Benefits		Other Postretirement Benefits		Expected Medicare Part D Subsidy
	(In thousands)
2013	$	23,193	$	6,099	$	256
2014	23,386		6,134		248
2015	23,646		6,127		239
2016	23,954		6,082		228
2017	24,531		6,083		217
2018 - 2022	128,971		29,051		896

Multiemployer plans

	EIN/Pension Plan Number	Pension Protection Act Zone Status		FIP/RP Status Pending/Implemented	Contributions						Surcharge Imposed	Expiration Date of Collective Bargaining Agreement
Pension Fund		2012	2011		2012		2011		2010
					(In thousands)
Edison Pension Plan	93-6061681-001	Green as of 12/31/2012	Green as of 12/31/2011	No	$	5,171	$	2,700	$	1,933	No	12/31/2014
IBEW Local 38 Pension Plan	34-6574238-001	Yellow as of 4/30/2012	Yellow as of 4/30/2011	Implemented	2,771		1,469		1,277		No	4/27/2014
IBEW Local No. 82 Pension Plan	31-6127268-001	Red as of 6/30/2012	Red as of 6/30/2011	Implemented	1,093		1,331		1,569		No	12/1/2013
IBEW Local 648 Pension Plan	31-6134845-001	Red as of 2/29/2012	Red as of 2/28/2011	Implemented	564		722		781		No	8/31/2015
Laborers Pension Trust Fund for Northern California	94-6277608-001	Yellow as of 5/31/2012	Yellow as of 5/31/2011	Implemented	567		628		413		No	6/30/2011*– 6/30/2012*
Local Union 212 IBEW Pension Trust Fund	31-6127280-001	Yellow as of 4/30/2012	Yellow as of 4/30/2011	Implemented	664		776		679		No	6/2/2013
National Electrical Benefit Fund	53-0181657-001	Green	Green	No	5,603		4,841		4,826		No	8/31/2011*– 12/31/2016
OE Pension Trust Fund	94-6090764-001	Yellow as of 12/31/2012	Yellow as of 12/31/2011	Implemented	1,156		1,367		1,035		No	6/30/2010*–3/31/2016
Operating Engineers Local 800 & WY Contractors Association, Inc. Pension Plan for Wyoming	83-6011320-001	Red as of 12/31/2012	Red as of 12/31/2011	Implemented	91		96		106		No	10/31/2005*
Operating Engineers Pension Trust	95-6032478-001	Red as of 6/30/2012	Red as of 6/30/2011	Implemented	761		458		343		No	6/30/2013– 12/31/2016
Other funds					16,338		14,770		17,314
Total contributions					$	34,779	$	29,158	$	30,276

* Plan includes collective bargaining agreements which have expired. The agreements contain provisions that automatically renew the existing contracts in lieu of a new negotiated collective bargaining agreement.

The Company was listed in the plans' Forms 5500 as providing more than 5 percent of the total contributions for the following plans and plan years:

Pension Fund	Year Contributions to Plan Exceeded More Than 5 Percent of Total Contributions (as of December 31 of the Plan's Year-End)
Defined Benefit Pension Plan of AGC-IUOE Local 701 Pension Trust Fund	2010
Edison Pension Plan	2011 and 2010
Eighth District Electrical Pension Fund	2010
IBEW Local 38 Pension Plan	2011 and 2010
IBEW Local No. 82 Pension Plan	2011 and 2010
Local Union No. 124 IBEW Pension Trust Fund	2011 and 2010
Local Union 212 IBEW Pension Trust Fund	2011 and 2010
IBEW Local Union No. 357 Pension Plan A	2011 and 2010
IBEW Local 648 Pension Plan	2011 and 2010
Idaho Plumbers and Pipefitters Pension Plan	2011 and 2010
Minnesota Teamsters Construction Division Pension Fund	2011 and 2010
Operating Engineers Local 800 & WY Contractors Association, Inc. Pension Plan for Wyoming	2011 and 2010
Plumbers and Pipefitters Local 162 Pension Fund	2010
Pension and Retirement Plan of Plumbers and Pipefitters Union Local No. 525	2011