Pension Plans and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2013

Compensation And Retirement Disclosure [Abstract]

Net Periodic Benefit Cost for Defined Benefit Plans

Net periodic defined benefit cost for defined benefit plans consisted of the following:

	Pension benefits						Other postretirement benefits
	Three months ended June 30
	2013			2012			2013			2012
	(in thousands)
Service cost	$	6,130			6,875			171			159
Interest cost on projected benefit obligation		14,939			15,418			670			919
Expected return on plan assets		(21,802	)		(17,581	)		—			—
Amortization of prior service cost		(1,628	)		(1,629	)		(329	)		10
Amortization of net actuarial loss		10,138			9,183			80			165
Net periodic benefit cost	$	7,777			12,266			592			1,253

	Pension benefits						Other postretirement benefits
	Six months ended June 30
	2013			2012			2013			2012
	(in thousands)
Service cost	$	12,180			14,775			371			334
Interest cost on projected benefit obligation		30,065			31,018			1,345			1,869
Expected return on plan assets		(43,677	)		(35,256	)		—			—
Amortization of prior service cost		(3,278	)		(3,279	)		(679	)		10
Amortization of net actuarial loss		20,538			18,583			180			265
Net periodic benefit cost	$	15,828			25,841			1,217			2,478