Contingencies and Legacy Environmental Commitments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended			1 Months Ended		1 Months Ended	3 Months Ended			12 Months Ended
	Mar. 31, 2014 Location	Mar. 31, 2013	Mar. 31, 2012	Jul. 31, 2001 Glen Head, New York	Mar. 31, 2014 Glen Head, New York	Mar. 31, 2014 Federal Labs	Jun. 30, 2005 Federal Labs	Dec. 31, 2003 Federal Labs	Jun. 30, 1999 Federal Labs	Mar. 31, 2014 Federal Labs Minimum	Mar. 31, 2014 Federal Labs Maximum	Mar. 31, 2014 Other Properties
Site Contingency [Line Items]
Aggregate environmental liability	$ 10,323	$ 12,684			$ 3,154	$ 4,954						$ 2,215
Cost-sharing related to environmental liabilities	1,918	1,472
Environmental costs	1,487	1,245	1,177					200
Number of locations for participating in environmental assessments and remediation work	8
Time frame for environmental liabilities	30 years									20 years	30 years
Property "held for sale"					3,800
Sale of environmental remediation property				4,000
Additional environmental remediation expense								200
Percentage of environmental costs paid by Federal Government							45.00%		50.00%
Percentage of environmental costs payable						26.00%
Percentage of environmental costs payable thereafter						33.50%
Increase in other current assets						793
Increase in other long term assets						359
Cost-sharing receivable						1,152
Reduction in remaining environmental liability	$ 1,207