Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income by Component, Net of Tax (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jun. 28, 2015	Jul. 03, 2016	Jun. 28, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 895.4
Other comprehensive income	$ 15.0	$ 6.2	18.5	$ 0.7
Ending balance	934.1	844.5	934.1	844.5
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(11.0)	(11.6)	(22.6)	(3.0)
Other comprehensive income (loss) before reclassifications	(0.6)	2.7	11.3	(5.7)
Amounts reclassified from accumulated other comprehensive income	0.0	0.0	(0.3)	(0.2)
Other comprehensive income	(0.6)	2.7	11.0	(5.9)
Ending balance	(11.6)	(8.9)	(11.6)	(8.9)
Unrealized Gains and Losses on Investment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	76.8	59.4	84.9	56.3
Other comprehensive income (loss) before reclassifications	15.6	3.5	7.5	6.6
Amounts reclassified from accumulated other comprehensive income	0.0	0.0	0.0	0.0
Other comprehensive income	15.6	3.5	7.5	6.6
Ending balance	92.4	62.9	92.4	62.9
Pension Liability Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1.6)	(2.2)	(1.6)	(2.2)
Other comprehensive income (loss) before reclassifications	0.0	0.0	0.0	0.0
Amounts reclassified from accumulated other comprehensive income	0.0	0.0	0.0	0.0
Other comprehensive income	0.0	0.0	0.0	0.0
Ending balance	(1.6)	(2.2)	(1.6)	(2.2)
Accumulated Other Comprehensive Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	64.2	45.6	60.7	51.1
Other comprehensive income (loss) before reclassifications	15.0	6.2	18.8	0.9
Amounts reclassified from accumulated other comprehensive income	0.0	0.0	(0.3)	(0.2)
Other comprehensive income	15.0	6.2	18.5	0.7
Ending balance	$ 79.2	$ 51.8	$ 79.2	$ 51.8