Pension Plan and Other Postretirement Benefits (Tables)

9 Months Ended

Sep. 30, 2012

Pension Plan And Other Postretirement Benefits [Abstract]

Net Periodic Pension and Other Postretirement Benefit Costs

	Pension Benefits
	For the three months ended				For the nine months ended
	September 30,				September 30,
	2012		2011		2012		2011
	(in thousands)
Service cost	$	2,736	$	2,330	$	8,207	$	6,992
Interest cost		1,013		918		3,038		2,753
Expected return on plan assets		(1,356)		(1,099)		(4,069)		(3,298)
Amortization of prior service cost		71		86		214		258
Amortization of net loss		305		214		915		642
Net periodic benefit cost	$	2,769	$	2,449	$	8,305	$	7,347
	Postretirement Benefits
	For the three months ended				For the nine months ended
	September 30,				September 30,
	2012		2011		2012		2011
	(in thousands)
Service cost	$	458	$	338	$	1,374	$	1,015
Interest cost		100		63		299		189
Amortization of transition obligation		16		16		48		48
Amortization of prior service cost		4		4		11		11
Amortization of net loss		23		2		69		8
Net periodic benefit cost	$	601	$	423	$	1,801	$	1,271