Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2013

Retirement Benefits

Schedule of net periodic benefit pension cost

Net periodic benefit cost, some of which is capitalized as a component of labor cost and some of which is deferred as a regulatory asset, is comprised of the following components and is shown for our noncontributory defined benefit pension plan, our supplemental retirement program (SERP) and other postretirement benefits (OPEB) (in thousands):

	Three months ended June 30,
	Pension Benefits						SERP						OPEB
	2013			2012			2013			2012			2013			2012
Service cost	$	1,859		$	1,628		$	52		$	7		$	715		$	565
Interest cost	2,523			2,551			94			56			922			1,032
Expected return on plan assets	(3,089		)	(3,076		)	—			—			(1,077		)	(1,041		)
Amortization of prior service cost (1)	133			133			(2		)	(2		)	(253		)	(253		)
Amortization of net actuarial loss (1)	2,632			1,950			180			76			481			468
Net periodic benefit cost	$	4,058		$	3,186		$	324		$	137		$	788		$	771

	Six months ended June 30,
	Pension Benefits						SERP						OPEB
	2013			2012			2013			2012			2013			2012
Service cost	$	3,727		$	3,256		$	67		$	15		$	1,470		$	1,129
Interest cost	5,031			5,102			157			111			1,913			2,065
Expected return on plan assets	(6,214		)	(6,151		)	—			—			(2,176		)	(2,083		)
Amortization of prior service cost (1)	266			266			(4		)	(4		)	(505		)	(505		)
Amortization of net actuarial loss (1)	5,223			3,899			284			153			1,131			935
Net periodic benefit cost	$	8,033		$	6,372		$	504		$	275		$	1,833		$	1,541

	Twelve months ended June 30,
	Pension Benefits						SERP						OPEB
	2013			2012			2013			2012			2013			2012
Service cost	$	6,732		$	6,054		$	104		$	62		$	2,742		$	2,262
Interest cost	10,187			10,305			308			203			3,885			4,257
Expected return on plan assets	(12,372		)	(11,721		)	—			—			(4,229		)	(4,161		)
Amortization of prior service cost (1)	531			532			(8		)	(8		)	(1,011		)	(1,011		)
Amortization of net actuarial loss (1)	9,259			6,647			520			238			1,858			1,816
Net periodic benefit cost	$	14,337		$	11,817		$	924		$	495		$	3,245		$	3,163

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