Business Segments, Significant Customer and Geographic Information (Details 4)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Percentage of revenues by geographic region derived from shipments to, or contract, service and other revenues from, external customers located outside the U.S.
Percentage of total net sales and contract revenues	5.00%	4.00%	2.00%
Middle East | Net sales and contract revenues
Percentage of revenues by geographic region derived from shipments to, or contract, service and other revenues from, external customers located outside the U.S.
Percentage of total net sales and contract revenues	4.00%	3.00%
Asia | Net sales and contract revenues
Percentage of revenues by geographic region derived from shipments to, or contract, service and other revenues from, external customers located outside the U.S.
Percentage of total net sales and contract revenues			1.00%
Other | Net sales and contract revenues
Percentage of revenues by geographic region derived from shipments to, or contract, service and other revenues from, external customers located outside the U.S.
Percentage of total net sales and contract revenues	1.00%	1.00%	1.00%