Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Dec. 28, 2014	Dec. 29, 2013	Dec. 28, 2014	Dec. 29, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 22,435us-gaap_NetIncomeLoss	$ 20,586us-gaap_NetIncomeLoss	$ 39,445us-gaap_NetIncomeLoss	$ 28,513us-gaap_NetIncomeLoss
Changes in fair value of marketable securities:
Changes in unrealized gains	(329)	(35)	(477)	(1,354)
Net realized losses (gains) reclassified into earnings	(3)	(84)	124	(343)
Total changes in fair value of marketable securities	(332)	(119)	(353)	(1,697)
Foreign currency translation adjustments	(391)	101	(602)	59
Total other comprehensive loss	(723)	(18)	(955)	(1,638)
Comprehensive income	$ 21,712us-gaap_ComprehensiveIncomeNetOfTax	$ 20,568us-gaap_ComprehensiveIncomeNetOfTax	$ 38,490us-gaap_ComprehensiveIncomeNetOfTax	$ 26,875us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature, attributable to parent entity.

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Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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