Marketable Securities - Held-to-Maturity (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 24, 2017	Dec. 25, 2016
Short-term Marketable Securities | Minimum
Schedule of Held-to-maturity Securities [Line Items]
Remaining maturities on short-term and long-term marketable securities	1 month
Short-term Marketable Securities | Maximum
Schedule of Held-to-maturity Securities [Line Items]
Remaining maturities on short-term and long-term marketable securities	12 months
Long-term Marketable Securities | Minimum
Schedule of Held-to-maturity Securities [Line Items]
Remaining maturities on short-term and long-term marketable securities	13 months
Long-term Marketable Securities | Maximum
Schedule of Held-to-maturity Securities [Line Items]
Remaining maturities on short-term and long-term marketable securities	34 months
Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term HTM securities		$ 449,535
Long-term HTM securities		187,299
Debt Securities | US Treasury Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term HTM securities		150,623
Long-term HTM securities		14,792
Debt Securities | Corporate Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term HTM securities		150,599
Long-term HTM securities		61,775
Debt Securities | US Government Agencies Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Short-term HTM securities		64,135
Long-term HTM securities		110,732
Debt Securities | Commercial paper
Schedule of Held-to-maturity Securities [Line Items]
Short-term HTM securities		$ 84,178