Business Acquisitions (Narrative) (Details) - USD ($) $ in Thousands, shares in Millions			3 Months Ended				12 Months Ended
	Apr. 04, 2016	Aug. 03, 2015	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Jun. 30, 2016	Jul. 17, 2014	Apr. 01, 2014
Business Acquisition [Line Items]
Non-cash consideration, exchange of employee stock awards (amount)							$ 7,470	$ 4,052
Net Loss Attributable to Noncontrolling Interest			$ 0	$ 0	$ 0	$ 207	0	207	$ 3,684
Atmel Corporation
Business Acquisition [Line Items]
Cash paid for shares	$ 2,980,000
Shares issued in acquisition	10.1
Equity interest issued or issuable, value assigned	$ 486,100
Separately recognized transactions, expenses and losses recognized	14,900
Consideration transferred, share based payment awards	7,470
Total consideration transferred	3,470,000
Recognized identifiable assets acquired and liabilities assumed, liabilities	653,100						653,058			$ 722,240
Payments to acquire businesses portion funded by foreign subsidiaries cash balances	2,040,000
Payments to acquire businesses portion funded by additional line of credit borrowings	$ 940,000
Useful life (in years)	9 years
Net deferred tax liability for future amortization expense of acquired intangible assets	$ 178,100
Revenue of acquiree included in statement of income since the acquisition date							1,062,600
Pro forma information, earnings or loss of acquiree since acquisition date							(314,300)
Long-term deferred tax assets							$ 46,700			$ 49,466
Micrel Incorporated
Business Acquisition [Line Items]
Cash paid for shares		$ 430,000
Shares issued in acquisition		8.6
Non-cash consideration, exchange of employee stock awards (amount)		$ 4,100
Total consideration transferred		816,200
Recognized identifiable assets acquired and liabilities assumed, liabilities		138,419
Net deferred tax liability for future amortization expense of acquired intangible assets		99,700
Cash paid in a business combination for employee vested stock awards		13,100
Long-term deferred tax assets		$ 11,400
ISSC Technologies Corporation
Business Acquisition [Line Items]
Recognized identifiable assets acquired and liabilities assumed, liabilities											$ 56,557
Percentage of interest acquired in acquisition						100.00%					83.50%
Supertex Inc.
Business Acquisition [Line Items]
Non-cash consideration, exchange of employee stock awards (amount)									1,622
Recognized identifiable assets acquired and liabilities assumed, liabilities												$ 64,012
Noncontrolling Interest | ISSC Technologies Corporation
Business Acquisition [Line Items]
Net Loss Attributable to Noncontrolling Interest								$ 200	$ 3,700