Shareholders' Equity (Equity Component) (Details) Tangible_Equity_Unit in Thousands	3 Months Ended		12 Months Ended
	Dec. 30, 2017 Tangible_Equity_Unit shares	Jul. 02, 2016 trade_day $ / shares $ / per_TEU shares	Sep. 29, 2018 trade_day Tangible_Equity_Unit shares	Sep. 30, 2017 Tangible_Equity_Unit
Debt Instrument [Line Items]
Fair value price per TEU (in dollars per TEU) | $ / per_TEU		100
Equity Component [Member]
Debt Instrument [Line Items]
Fair value price per TEU (in dollars per TEU) | $ / per_TEU		76.19
Threshold consecutive trading days | trade_day		20	20
Threshold trading days | trade_day		23
Settlement of tangible equity units, settled (in units) | Tangible_Equity_Unit	473
Settlement of tangible equity units (in shares)	939,000
Tangible equity units, outstanding | Tangible_Equity_Unit			677	677
Equity Component [Member] | Common Class A [Member]
Debt Instrument [Line Items]
Threshold stock appreciation price (in dollars per share) | $ / shares		$ 50.40
Convertible reference price (in dollars per share) | $ / shares		$ 42.00
Equity Component [Member] | Minimum [Member] | Common Class A [Member]
Debt Instrument [Line Items]
Number of equity instruments per contract (in shares)	1.9841	1.9841	1.9841
Equity Component [Member] | Maximum [Member] | Common Class A [Member]
Debt Instrument [Line Items]
Number of equity instruments per contract (in shares)		2.3810	2.3810