Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2012

Pension and Post-Retirement Medical Plans:

Employee benefit plans

Schedule of Pension Plan's funded status and amounts recognized in balance sheets and the components of net pension cost and accrued post-retirement liability

	Pension Benefits						Post-Retirement Medical Benefits
(dollars in thousands)	2012			2011			2012			2011
Change in Projected Benefit Obligation:
Projected benefit obligation at beginning of year	$	146,127		$	118,766		$	12,448		$	12,057
Service cost	6,675			5,624			419			391
Interest cost	6,657			6,524			534			549
Actuarial loss (gain)	7,759			18,719			(657		)	(236		)
Benefits/expenses paid	(3,988		)	(3,506		)	(448		)	(313		)
Projected benefit obligation at end of year	$	163,230		$	146,127		$	12,296		$	12,448
Changes in Plan Assets:
Fair value of plan assets at beginning of year	$	92,910		$	90,179		$	7,916		$	6,959
Actual return on plan assets	12,599			(326		)	736			319
Employer contributions	6,117			6,563			155			951
Benefits/expenses paid	(3,988		)	(3,506		)	(448		)	(313		)
Fair value of plan assets at end of year	$	107,638		$	92,910		$	8,359		$	7,916
Funded Status:
Net amount recognized as accrued pension cost	$	(55,592	)	$	(53,217	)	$	(3,937	)	$	(4,532	)

	Pension Benefits						Post-Retirement Medical Benefits
(in thousands)	2012			2011			2012			2011
Amounts recognized on the balance sheets:
Current liabilities	$	—		$	—		$	—		$	—
Non-current liabilities	(55,592		)	(53,217		)	(3,937		)	(4,532		)
Net amount recognized	$	(55,592	)	$	(53,217	)	$	(3,937	)	$	(4,532	)
Amounts recognized in regulatory assets consist of:
Initial net obligation	$	—		$	—		$	837		$	1,256
Prior service cost (credit)	404			522			(633		)	(833		)
Net (gain) loss	48,648			49,983			(889		)	147
Regulatory assets (liabilities)	49,052			50,505			(685		)	570
Unfunded accrued pension cost	6,540			2,712			4,622			3,962
Net liability recognized	$	55,592		$	53,217		$	3,937		$	4,532
Changes in plan assets and benefit obligations recognized in regulatory assets:
Regulatory asset at beginning of year	$	50,505		$	26,471		$	570		$	1,045
Net loss (gain)	1,700			25,394			(1,036		)	(256		)
Amortization of initial net obligation	—			—			(419		)	(419		)
Amortization of prior service (cost) credit	(118		)	(118		)	200			200
Amortization of net loss	(3,035		)	(1,242		)	—			—
Total change in regulatory asset	(1,453		)	24,034			(1,255		)	(475		)
Regulatory asset (liability) at end of year	$	49,052		$	50,505		$	(685	)	$	570
Net periodic pension costs	$	9,945		$	7,159		$	815		$	861
Change in regulatory asset	(1,453		)	24,034			(1,255		)	(475		)
Total recognized in net periodic pension cost and regulatory asset (liability)	$	8,492		$	31,193		$	(440	)	$	386
Estimated amounts that will be amortized from regulatory asset over the next fiscal year:
Initial net obligation	$	—		$	—		$	(419	)	$	(419	)
Prior service cost	(118		)	(118		)	200			200
Net loss	(2,846		)	(3,114		)	—			—
Additional year-end information for plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	$	163,230		$	146,127		$	12,296		$	12,448
Accumulated benefit obligation	138,230			122,399			N/A			N/A
Fair value of plan assets	107,638			92,910			8,359			7,916
Weighted-average assumptions used to determine benefit obligations at December 31:
Discount rate	4.30		%	4.65		%	3.75		%	4.45		%
Rate of compensation increase	4.00		%	4.00		%	N/A			N/A

Schedule of components of net periodic pension and post-retirement benefits cost, before allocation to the overhead pool

	Pension Benefits									Post-Retirement  Medical Benefits
(dollars in thousands, except percent)	2012			2011			2010			2012			2011			2010
Components of Net Periodic Benefits Cost:
Service cost	$	6,675		$	5,624		$	4,795		$	419		$	391		$	390
Interest cost	6,657			6,524			6,104			534			549			626
Expected return on plan assets	(6,540		)	(6,349		)	(5,253		)	(357		)	(298		)	(255		)
Amortization of transition	—			—			—			419			419			419
Amortization of prior service cost (credit)	118			118			118			(200		)	(200		)	(200		)
Amortization of actuarial loss	3,035			1,242			1,170			—			—			—
Net periodic pension cost under accounting standards	$	9,945		$	7,159		$	6,934		$	815		$	861		$	980
Regulatory adjustment - deferred	(2,305		)	(209		)	(1,823		)	—			—			—
Total expense recognized, before allocation to overhead pool	$	7,640		$	6,950		$	5,111		$	815		$	861		$	980
Weighted-average assumptions used to determine net periodic cost:
Discount rate	4.65		%	5.55		%	6.05		%	4.45		%	5.20		%	5.85		%
Expected long-term return on plan assets	7.00		%	7.00		%	7.00		%	*			*			*
Rate of compensation increase	4.00		%	4.00		%	4.00		%	N/A			N/A			N/A

*7.0% for union plan, 4.2% for non-union, net of income taxes in 2012, 2011 and 2010.

Schedule of pension and post-retirement plan weighted-average asset allocations, by asset category

	Pension Benefits				Post-Retirement Medical Benefits
Asset Category	2012		2011		2012		2011
Actual Asset Allocations:
Equity securities	60	%	56	%	61	%	60	%
Debt securities	39	%	42	%	38	%	39	%
Cash equivalents	1	%	2	%	1	%	1	%
Total	100	%	100	%	100	%	100	%

Schedule of pension and post-retirement plan target asset allocations

Target Asset Allocations for 2013:	Pension Benefits		Post-retirement Medical Benefits
Equity securities	60	%	60	%
Debt securities	40	%	40	%
Total	100	%	100	%

Schedule of pension and post-retirement plans' investment assets measured at fair value

	Fair Value as of December 31, 2012
(dollars in thousands)	Level 1		Level 2	Level 3	Total
Fair Value of Pension Plan Assets:
Cash equivalents	$	1,721	—	—	$	1,721
Fixed income securities	41,590		—	—	41,590
Equity securities:
U.S. small cap stocks	5,396		—	—	5,396
U.S. mid cap stocks	10,722		—	—	10,722
U.S. large cap stocks	31,966		—	—	31,966
International funds	10,797		—	—	10,797
Real estate funds	5,446		—	—	5,446
Total equity securities	64,327		—	—	64,327
Total investments measured at fair value	$	107,638	—	—	$	107,638
Fair Value of Post-Retirement Plan Assets:
Cash equivalents	$	65	—	—	$	65
Fixed income	3,192		—	—	3,192
U.S. equity securities (large cap stocks)	5,102		—	—	5,102
Total investments measured at fair value	$	8,359	—	—	$	8,359

	Fair Value as of December 31, 2011
(dollars in thousands)	Level 1		Level 2	Level 3	Total
Fair Value of Pension Plan Assets:
Cash equivalents	$	1,682	—	—	$	1,682
Fixed income securities	38,900		—	—	38,900
Equity securities:
U.S. small cap stocks	4,288		—	—	4,288
U.S. mid cap stocks	8,616		—	—	8,616
U.S. large cap stocks	26,803		—	—	26,803
International funds	7,997		—	—	7,997
Real estate funds	4,624		—	—	4,624
Total equity securities	52,328		—	—	52,328
Total investments measured at fair value	$	92,910	—	—	$	92,910
Fair Value of Post-Retirement Plan Assets:
Cash equivalents	$	100	—	—	$	100
Fixed income	3,064		—	—	3,064
U.S. equity securities (large cap stocks)	4,752		—	—	4,752
Total investments measured at fair value	$	7,916	—	—	$	7,916

Schedule of estimated future benefit payments

Registrant’s estimated future benefit payments at December 31, 2012 for the next five years and thereafter are as follows (in thousands):

	Pension Benefits		Post-RetirementMedical Benefits
2013	$	4,336	$	477
2014	4,811		509
2015	5,325		578
2016	5,892		652
2017	6,503		728
Thereafter	42,491		4,690
Total	$	69,358	$	7,634

Schedule of effects of one-percentage-point change in assumed health care cost trend rates

(dollars in thousands)	1-Percentage-Point Increase		1-Percentage-Point Decrease
Effect on total of service and interest cost components	$	102	$	(88	)
Effect on post-retirement benefit obligation	$	1,464	$	(1,263	)

SERP

Employee benefit plans

Schedule of Pension Plan's funded status and amounts recognized in balance sheets and the components of net pension cost and accrued post-retirement liability

(dollars in thousands)	2012			2011
Change in Benefit Obligation:
Benefit obligation at beginning of year	$	10,604		$	8,468
Service cost	731			600
Interest cost	488			464
Actuarial loss	803			1,292
Benefits paid	(220		)	(220		)
Benefit obligation at end of year	$	12,406		$	10,604
Changes in Plan Assets:
Fair value of plan assets at beginning of year	—			—
Fair value of plan assets at end of year	—			—
Funded Status:
Net amount recognized as accrued pension cost	$	(12,406	)	$	(10,604	)

(in thousands)	2012			2011
Amounts recognized on the balance sheets:
Current liabilities	$	(317	)	$	(231	)
Non-current liabilities	(12,089		)	(10,373		)
Net amount recognized	$	(12,406	)	$	(10,604	)
Amounts recognized in regulatory assets consist of:
Prior service cost	$	475		$	636
Net loss	3,709			3,212
Regulatory assets	4,184			3,848
Unfunded accrued pension cost	8,222			6,756
Net liability recognized	$	12,406		$	10,604
Changes in plan assets and benefit obligations recognized in regulatory assets consist of:
Regulatory asset at beginning of year	$	3,848		$	2,852
Net loss	805			1,291
Amortization of prior service credit	(161		)	(161		)
Amortization of net loss	(308		)	(134		)
Total change in regulatory asset	336			996
Regulatory asset at end of year	$	4,184		$	3,848
Net periodic pension cost	$	1,687		$	1,359
Change in regulatory asset	336			996
Total recognized in net periodic pension and net income	$	2,023		$	2,355
Estimated amounts that will be amortized from regulatory asset over the next fiscal year:
Initial net asset (obligation)	—			—
Prior service cost	$	(161	)	$	(161	)
Net loss	(339		)	(307		)
Additional year-end information for plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	$	12,406		$	10,604
Accumulated benefit obligation	9,601			7,639
Fair value of plan assets	—			—
Weighted-average assumptions used to determine benefit obligations:
Discount rate	4.20		%	4.65		%
Rate of compensation increase	4.00		%	4.00		%

Schedule of components of net periodic pension and post-retirement benefits cost, before allocation to the overhead pool

(dollars in thousands, except percent)	2012			2011			2010
Components of Net Periodic Benefits Cost:
Service cost	$	731		$	600		$	433
Interest cost	488			464			354
Amortization of prior service cost	161			161			161
Amortization of net loss	307			134			—
Net periodic pension cost	$	1,687		$	1,359		$	948
Weighted-average assumptions used to determine net periodic cost:
Discount rate	4.65		%	5.55		%	6.05		%
Rate of compensation increase	4.00		%	4.00		%	4.00		%

Schedule of pension and post-retirement plans' investment assets measured at fair value

	Fair Value as of December 31, 2012
(dollars in thousands)	Level 1		Level 2	Level 3	Total
Fair Value of Assets held in Rabbi Trust:
Cash equivalents	$	116	—	—	$	116
Fixed income securities	1,878		—	—	1,878
Equity securities	2,822		—	—	2,822
Total investments measured at fair value	$	4,816	—	—	$	4,816

	Fair Value as of December 31, 2011
(dollars in thousands)	Level 1		Level 2	Level 3	Total
Fair Value of Assets held in Rabbi Trust:
Cash equivalents	$	9	—	—	$	9
Fixed income securities	1,081		—	—	1,081
Equity securities	1,739		—	—	1,739
Total investments measured at fair value	$	2,829	—	—	$	2,829

Schedule of estimated future benefit payments

Benefit Payments:  Registrant’s estimated future benefit payments for the SERP at December 31, 2012 for the next ten years are as follows (in thousands):

2013	$	318
2014	317
2015	316
2016	337
2017	406
Thereafter	3,581
Total	$	5,275