Pension and Other Benefit Plans (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended			3 Months Ended				9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2012	Dec. 31, 2012 Pension Plans, Defined Benefit [Member]	Dec. 31, 2011 Pension Plans, Defined Benefit [Member]	Dec. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit [Member]	Dec. 31, 2011 Other Postretirement Benefit Plans, Defined Benefit [Member]	Dec. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit [Member]	Dec. 31, 2011 Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension cost	$ 5,577	$ 6,177		$ 1,859	$ 1,668	$ 114	$ 202	$ 341	$ 605
Total liabilities	326,282		354,941
Other Liabilities Noncurrent	92,035		99,143
Accrued Liabilities Current	$ 51,603		$ 61,713