Fair Value Measurements - Estimated Fair Values of Convertible Notes (Detail) $ in Millions	Jun. 27, 2015 USD ($)
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair values of debt instruments	$ 1,846.7
2010 Notes
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair values of debt instruments	746.2
2012 Notes
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair values of debt instruments	651.3
2013 Notes
Estimated Fair Value Of Financial Instruments [Line Items]
Estimated fair values of debt instruments	$ 449.2