Business Acquisitions (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017	Apr. 04, 2016
Assets acquired
Goodwill	$ 2,299,009	$ 2,299,009
Atmel Corporation
Assets acquired
Cash and cash equivalents			$ 230,266
Accounts receivable			141,359
Inventories			335,163
Prepaid expenses and other current assets			28,360
Assets held for sale			32,006
Property, plant and equipment, net			129,884
Goodwill			1,286,371
Purchased intangible assets			1,888,392
Long-term deferred tax assets			46,700
Other assets			7,535
Total assets acquired			4,126,036
Liabilities assumed
Accounts payable			(55,686)
Other current liabilities			(120,955)
Long-term line of credit			(192,000)
Deferred tax liabilities			(27,552)
Long-term income tax payable			(115,177)
Other long-term liabilities			(141,688)
Total liabilities assumed			(653,058)
Purchase price allocated			$ 3,472,978