Employee Benefit Plans

9 Months Ended

Sep. 30, 2011

Employee Benefit Plans [Abstract]

Employee Benefit Plans

7. Employee Benefit Plans

We sponsor two union pension plans for certain employees and a pension plan primarily for salaried employees, a postretirement benefit plan for selected employees and a defined contribution plan. The following tables present our consolidated net periodic benefit costs related to these plans during the three and nine months ended September 30, 2010 and 2011 (in thousands):

	Three Months  Ended September 30, 2010						Three Months  Ended September 30, 2011
	Pension Benefits			Other  Post- Retirement Benefits			Pension Benefits			Other  Post- Retirement Benefits
Components of net periodic benefit costs:
Service cost	$	1,687		$	63		$	3,251		$	141
Interest cost	840			338			1,358			230
Expected return on plan assets	(890		)	—			(1,225		)	—
Amortization of prior service cost (credit)	76			(213		)	76			(212		)
Amortization of actuarial loss	138			100			766			1
Settlement cost	—			—			70			—
Net periodic benefit cost	$	1,851		$	288		$	4,296		$	160

	Nine Months  Ended September 30, 2010						Nine Months  Ended September 30, 2011
	Pension Benefits			Other  Post- Retirement Benefits			Pension Benefits			Other  Post- Retirement Benefits
Components of net periodic benefit costs:
Service cost	$	5,040		$	239		$	7,221		$	323
Interest cost	2,506			744			3,257			749
Expected return on plan assets	(2,664		)	—			(3,268		)	—
Amortization of prior service cost (credit)	230			(638		)	230			(638		)
Amortization of actuarial loss	388			100			1,068			126
Settlement cost	—			—			70			—
Net periodic benefit cost	$	5,500		$	445		$	8,578		$	560

Contributions estimated to be paid into the plans in 2011 are $9.4 million and $0.5 million for the pension and other postretirement benefit plans, respectively.