Accumulated Other Comprehensive Loss (Reclassifications out of Accumulated Other Comprehensive Loss to Net Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	$ (33,809)	$ (31,014)	$ (121,432)	$ (124,701)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Defined Benefit Plans Adjustment
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	144	704	432	2,068
Tax benefit	(58)	(285)	(175)	(863)
Net of tax	$ 86	$ 419	$ 257	$ 1,205