Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Capital in Excess of Par value of Common Stock	Retained Earnings	Accumulated Other Comprehensive Income
Balance (in shares) at Sep. 30, 2012		90.3
Balance at Sep. 30, 2012	$ 928.1	$ 18.1	$ 678.9	$ 231.8	$ (0.7)
Proceeds from exercise of stock options (in shares)		1.9
Proceeds from exercise of stock options	25.3	$ 0.4	24.9
Tax withholding on restricted stock units	(0.9)		(0.9)
Grants and cancellations of restricted share awards (in shares)		1.6
Grants and cancellations of restricted share awards	0.0	$ 0.3	(0.3)
Issuance of stock awards related to acquisition	0.0		0.0
Stock-based compensation expense	35.2
Stock-based compensation	35.2
Other comprehensive income, net of tax	0.7				0.7
Net income	43.7			43.7
Balance (in shares) at Sep. 29, 2013		93.8
Balance at Sep. 29, 2013	1,032.1	$ 18.8	737.8	275.5	0.0
Proceeds from exercise of stock options (in shares)		1.5
Proceeds from exercise of stock options	19.2	$ 0.2	19.0
Tax withholding on restricted stock units	(1.5)		(1.5)
Grants and cancellations of restricted share awards (in shares)		0.3
Grants and cancellations of restricted share awards	0.0	$ 0.1	(0.1)
Stock-based compensation expense	43.9
Stock-based compensation	43.9
Other comprehensive income, net of tax	(1.2)				(1.2)
Net income	23.1			23.1
Balance (in shares) at Sep. 28, 2014		95.6
Balance at Sep. 28, 2014	1,115.6	$ 19.1	799.1	298.6	(1.2)
Proceeds from exercise of stock options (in shares)		2.1
Proceeds from exercise of stock options	48.4	$ 0.4	48.0
Tax withholding on restricted stock units	(18.1)		(18.1)
Grants and cancellations of restricted share awards (in shares)		0.1
Grants and cancellations of restricted share awards	0.0	$ 0.0	0.0
Issuance of stock awards related to acquisition	3.8		3.8
Stock-based compensation expense	49.8
Stock-based compensation	49.8
Other comprehensive income, net of tax	$ (1.9)				(1.9)
Repurchase of outstanding common stock (in shares)	(2.7)	(2.7)
Repurchase of outstanding common stock	$ (75.0)	$ (0.5)	(74.5)
Net income	84.6			84.6
Balance (in shares) at Sep. 27, 2015		95.1
Balance at Sep. 27, 2015	$ 1,207.2	$ 19.0	$ 808.1	$ 383.2	$ (3.1)