Pension Plan and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2013

Pension Plan and Other Postretirement Benefits

Components of net periodic benefit costs for the pension and other postretirement plans

	Three months Ended June 30
	Pension Plan						Other Benefits
	2013			2012			2013			2012
Service cost	$	4,658		$	3,709		$	1,695		$	1,330
Interest cost	4,063			3,864			1,109			1,005
Expected return on plan assets	(3,565		)	(2,886		)	(598		)	(448		)
Recognized net initial APBO (1)	N/A			N/A			2			69
Amortization of prior service cost	1,541			1,570			20			29
Recognized net actuarial loss	2,224			2,075			916			822
Net periodic benefit cost	$	8,921		$	8,332		$	3,144		$	2,807

	Six months Ended June 30
	Pension Plan						Other Benefits
	2013			2012			2013			2012
Service cost	$	9,316		$	7,725		$	3,390		$	2,747
Interest cost	8,126			7,643			2,218			1,972
Expected return on plan assets	(7,130		)	(5,779		)	(1,196		)	(916		)
Recognized net initial APBO (1)	N/A			N/A			4			138
Amortization of prior service cost	3,082			3,141			40			58
Recognized net actuarial loss	4,448			4,001			1,832			1,586
Net periodic benefit cost	$	17,842		$	16,731		$	6,288		$	5,585

(1) APBO - Accumulated postretirement benefit obligation