Benefit Plans and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2012

Benefit Plans and Other Postretirement Benefits

Schedule of components of net pension expense

	Pension Benefits						Other Postretirement Benefits
	Three months ended September 30,
	2012			2011			2012		2011
Service cost	$	1,911		$	2,183		$	45	$	50
Interest cost	5,387			6,182			169		212
Expected return on plan assets	(6,089		)	(7,399		)	—		—
Amortization of transition obligation	(27		)	(28		)	16		16
Amortization of prior service cost	535			676			—		—
Amortization of net actuarial losses	4,484			3,209			242		325
Net pension expense	$	6,201		$	4,823		$	472	$	603

	Pension Benefits						Other Postretirement Benefits
	Nine months ended September 30,
	2012			2011			2012		2011
Service cost	$	5,795		$	5,150		$	134	$	150
Interest cost	16,340			16,573			508		636
Expected return on plan assets	(18,408		)	(17,852		)	—		—
Amortization of transition obligation	(81		)	(84		)	47		47
Amortization of prior service cost	1,610			1,666			—		—
Amortization of net actuarial losses	13,592			9,099			725		976
Net pension expense	$	18,848		$	14,552		$	1,414	$	1,809