Other Long-Term Liabilities (Detail) - USD ($) $ in Millions	Sep. 27, 2015	Sep. 28, 2014
Other Liabilities Disclosure [Abstract]
Unrecognized tax benefits	$ 19.8	$ 17.4
Deferred rent	11.2	13.7
Pension and retirement	8.9	8.9
Restructuring	3.4	3.8
Other	3.0	3.1
Total	$ 46.3	$ 46.9