Pension and Postretirement Benefits Net Periodic Pension Costs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension and Other Postretirement Benefit Expense [Abstract]
Service cost	$ 530		$ 511	$ 1,078	$ 1,023
Interest cost	1,662		1,842	3,383	3,684
Expected return on plan assets	(1,519)		(1,571)	(3,037)	(3,140)
Amortization of prior service cost	49		55	102	110
Actuarial loss	760		500	1,517	998
Curtailment loss	0	1,261	0	77	0
Special termination benefit	0		0	1,184	0
Net periodic pension (benefit)	1,482		1,337	4,304	2,675
Contributions by employer	5,137
Additional contributions to the plans are expected during the rest of fiscal 2013	$ 7,574			$ 7,574