Retirement and Other Employee Benefits (Tables)

3 Months Ended

Mar. 31, 2016

Retirement and Other Employee 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 March 31,
	Pension						SERP						OPEB
	2016			2015			2016			2015			2016			2015
Service cost	$	1,949		$	1,883		$	45		$	43		$	813		$	920
Interest cost	2,633			2,503			108			92			1,156			1,164
Expected return on plan assets	(3,465		)	(3,390		)	—			—			(1,374		)	(1,312		)
Amortization of prior service cost (1)	(157		)	(157		)	(3		)	(11		)	(253		)	(253		)
Amortization of net actuarial loss (1)	2,106			2,345			139			140			258			681
Net periodic benefit cost	$	3,066		$	3,184		$	289		$	264		$	600		$	1,200

	Twelve months ended March 31,
	Pension						SERP						OPEB
	2016			2015			2016			2015			2016			2015
Service cost	$	7,508		$	6,722		$	161		$	167		$	3,606		$	2,914
Interest cost	10,408			10,589			398			393			4,663			4,442
Expected return on plan assets	(13,643		)	(13,173		)	—			—			(5,258		)	(4,916		)
Amortization of prior service cost (1)	(630		)	156			(35		)	(17		)	(1,011		)	(1,011		)
Amortization of net actuarial loss (1)	9,795			7,308			596			539			2,324			1,420
Net periodic benefit cost	$	13,438		$	11,602		$	1,120		$	1,082		$	4,324		$	2,849

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