Investments (Summary of Gross Unrealized Losses and Estimated Fair Value of Short-term Investments, Aggregated by Investment Type and Length of Time) (Details) $ in Thousands	Dec. 24, 2017 USD ($)	Jun. 25, 2017 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 219,155	$ 84,220
Unrealized Loss, Less than 12 Months	(1,467)	(263)
Fair Value, Greater than 12 Months	20,629	0
Unrealized Loss, Greater than 12 Months	(327)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	239,784	84,220
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 1,794	$ 263
Number of Securities with an Unrealized Loss, Less than 12 Months	148	67
Number of Securities with an Unrealized Loss, Greater than 12 Months	23	0
Number of Securities with an Unrealized Loss, Total	171	67
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	$ 115,005	$ 26,816
Unrealized Loss, Less than 12 Months	(897)	(68)
Fair Value, Greater than 12 Months	7,821	0
Unrealized Loss, Greater than 12 Months	(90)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	122,826	26,816
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	987	68
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	100,236	57,404
Unrealized Loss, Less than 12 Months	(563)	(195)
Fair Value, Greater than 12 Months	12,808	0
Unrealized Loss, Greater than 12 Months	(237)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	113,044	57,404
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	800	195
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than 12 Months	3,914	0
Unrealized Loss, Less than 12 Months	(7)	0
Fair Value, Greater than 12 Months	0	0
Unrealized Loss, Greater than 12 Months	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,914	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 7	$ 0

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
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-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

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