Employee Benefit Plans (Tables)

6 Months Ended

Jul. 31, 2011

Employee Benefit Plans [Abstract]

Net periodic pension and other postretirement benefit expense

	Three Months Ended July 31,
							Other
	Pension Benefits						Postretirement Benefits
(in thousands)	2011			2010			2011			2010
Net Periodic Benefit Cost:
Service cost	$	3,592		$	3,274		$	504		$	347
Interest cost		6,274			5,998			753			696
Expected return on plan assets		(4,849	)		(4,455	)		—			—
Amortization of prior service cost		267			269			(165	)		(165	)
Amortization of net loss		1,404			760			3			—
Net expense	$	6,688		$	5,846		$	1,095		$	878

	Six Months Ended July 31,
							Other
	Pension Benefits						Postretirement Benefits
(in thousands)	2011			2010			2011			2010
Net Periodic Benefit Cost:
Service cost	$	7,182		$	6,543		$	1,007		$	694
Interest cost		12,481			11,995			1,505			1,392
Expected return on plan assets		(9,697	)		(8,910	)		—			—
Amortization of prior service cost		533			538			(330	)		(330	)
Amortization of net loss		2,727			1,520			6			—
Net expense	$	13,226		$	11,686		$	2,188		$	1,756