Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 25, 2017	Jun. 25, 2017	Dec. 25, 2016	Dec. 27, 2015
Schedule of Held-to-maturity Securities [Line Items]
Unrecognized loss in other comprehensive income if marketable securities were classified as available-for-sale	$ 1,000
Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term marketable securities	382,569	$ 382,569	$ 449,535
Long-term marketable securities	220,708	220,708	187,299
Debt Securities | US Treasury Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term marketable securities	111,222	111,222	150,623
Long-term marketable securities	48,940	48,940	14,792
Debt Securities | Corporate Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term marketable securities	178,869	178,869	150,599
Long-term marketable securities	64,076	64,076	61,775
Debt Securities | U.S. governmental agency securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term marketable securities	50,488	50,488	64,135
Long-term marketable securities	107,692	107,692	110,732
Debt Securities | Certificates of Deposit
Schedule of Held-to-maturity Securities [Line Items]
Short-term marketable securities			11,102	$ 0
Debt Securities | Commercial Paper
Schedule of Held-to-maturity Securities [Line Items]
Short-term marketable securities	$ 30,888	$ 30,888	$ 84,178
Short-term Marketable Securities | Minimum
Schedule of Held-to-maturity Securities [Line Items]
Term of investments		1 month
Short-term Marketable Securities | Maximum
Schedule of Held-to-maturity Securities [Line Items]
Term of investments		12 months
Long-term Marketable Securities | Minimum
Schedule of Held-to-maturity Securities [Line Items]
Term of investments		13 months
Long-term Marketable Securities | Maximum
Schedule of Held-to-maturity Securities [Line Items]
Term of investments		32 months