Employee Benefit Plans (Tables)

3 Months Ended

Apr. 30, 2013

Compensation And Retirement Disclosure [Abstract]

Schedule of Net Periodic Pension and Other Postretirement Benefit Expense

Net periodic pension and other postretirement benefit expense included the following components:

	Three Months Ended April 30,
	Pension Benefits						Other Postretirement Benefits
(in thousands)	2013			2012			2013			2012
Net Periodic Benefit Cost:
Service cost	$	5,056		$	4,416		$	723		$	702
Interest cost		6,865			6,587			728			796
Expected return on plan assets		(4,950	)		(4,886	)		—			—
Amortization of prior service cost		243			254			(165	)		(165	)
Amortization of net loss		5,200			3,990			96			96
Net expense	$	12,414		$	10,361		$	1,382		$	1,429