Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Future minimum lease commitments under operating leases [Abstract]
Operating Leases, Future Minimum Payments Due, Current	$ 16,370
Operating Leases, Future Minimum Payments, Due in Two Years	12,350
Operating Leases, Future Minimum Payments, Due in Three Years	7,677
Operating Leases, Future Minimum Payments, Due in Four Years	3,098
Operating Leases, Future Minimum Payments, Due in Five Years	1,000
Operating Leases, Future Minimum Payments, Due Thereafter	667
Operating Leases, Total Future Minimum Payments Due	41,162
Rental expense under operating lease	23,300	$ 23,800	$ 21,500
Property, Plant and Equipment Purchase Commitment [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	30,200
Purchase Commitment, Other Obligations [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	57,600
Wafer Foundry Purchase Commitment [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	$ 52,400