Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

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The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

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Amount of other expense that is infrequent in occurrence or unusual in nature.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Special Charges (Details) (Unusual or Infrequent Item [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Unusual or Infrequent Item [Line Items]
Other Nonrecurring Expense	$ 2.8us-gaap_OtherNonrecurringExpense	$ 3.0us-gaap_OtherNonrecurringExpense	$ 32.2us-gaap_OtherNonrecurringExpense
SMSC Acquisition [Member]
Unusual or Infrequent Item [Line Items]
Severance related, office closing and other costs			16.3
SST acquisition [Member]
Unusual or Infrequent Item [Line Items]
Legal settlement costs			11.5
Roving Networks Acquisition [Member]
Unusual or Infrequent Item [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			$ 4.4