Benefit Plans and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2011

Benefit Plans and Other Postretirement Benefits

Schedule of net cost for pension benefits and other postretirement benefits

	Pension Benefits						Other Postretirement Benefits
	Three months ended September 30,
	2011			2010			2011		2010
Service cost	$	2,183		$	1,439		$	50	$	41
Interest cost	6,182			5,661			212		197
Expected return on plan assets	(7,399		)	(5,643		)	—		—
Amortization of transition obligation	(28		)	(27		)	16		16
Amortization of prior service cost	676			38			—		—
Amortization of net actuarial losses	3,209			2,631			325		221
Net pension expense	$	4,823		$	4,099		$	603	$	475

	Pension Benefits						Other Postretirement Benefits
	Nine months ended September 30,
	2011			2010			2011		2010
Service cost	$	5,150		$	4,333		$	150	$	124
Interest cost	16,573			17,002			636		590
Expected return on plan assets	(17,852		)	(16,917		)	—		—
Amortization of transition obligation	(84		)	(81		)	47		47
Amortization of prior service cost	1,666			1,814			—		—
Amortization of net actuarial losses	9,099			7,889			976		663
Net pension expense	$	14,552		$	14,040		$	1,809	$	1,424