Stockholders' Equity - Changes in Accumulated Other Comprehensive Income by Component, Net of Tax (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of year		$ 1,159.5	$ 1,151.5
Balance at end of year		1,264.5	1,159.5	$ 1,151.5
Foreign currency translation adjustments:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of year		(15.7)	(6.9)	(23.3)
Other comprehensive income (loss) before classifications		2.5	(8.4)	16.4
Amounts reclassified from accumulated other comprehensive income	[1]	0.0	(0.4)	0.0
Net current-period other comprehensive income (loss)		2.5	(8.8)	16.4
Balance at end of year		(13.2)	(15.7)	(6.9)
Unrealized gains and losses on investment:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of year		0.0	140.0	83.8
Other comprehensive income (loss) before classifications		0.0	0.0	56.2
Amounts reclassified from accumulated other comprehensive income		0.0	0.0	0.0
Net current-period other comprehensive income (loss)		0.0	(140.0)	56.2
Balance at end of year		0.0	0.0	140.0
Pension liability adjustments:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of year		(1.4)	(2.3)	(1.8)
Other comprehensive income (loss) before classifications		(1.3)	0.8	(0.6)
Amounts reclassified from accumulated other comprehensive income	[2]	0.1	0.1	0.1
Net current-period other comprehensive income (loss)		(1.2)	0.9	(0.5)
Balance at end of year		(2.6)	(1.4)	(2.3)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of year		(17.1)	130.8	58.7
Balance at end of year		(15.8)	(17.1)	130.8
Accounting Standards Update 2016-01 | Unrealized gains and losses on investment:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative-effect adjustment from adoption of ASU 2016-01, Financial Instruments		$ 0.0	(140.0)	$ 0.0
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Cumulative-effect adjustment from adoption of ASU 2016-01, Financial Instruments			$ (140.0)

[1] Amount was recorded in the other expense, net line item in the consolidated statements of earnings.

[2] Amount was recorded in the SG&A expenses line item in the consolidated statements of earnings.