Share-Based Compensation - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Dec. 31, 2011	May 17, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense	$ 28.0	$ 16.0
Tax related benefits recognized	5.0
Total unearned compensation costs related to performance share awards	$ 75.0
Total unearned compensation costs amortization period	2 years 1 month 18 days
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of exercised options	$ 34.0	8.0
Options, vested in period, fair value	$ 7.0	6.0
Vesting period	4 years
RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Other Award Types
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Settlement payments for awards	$ 2.0	$ 1.0
Share-equivalents issued (in shares)	(17,253)	(45,781)
Non-qualified Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax related benefits recognized	$ 1.0	$ 1.0
Intrinsic value of exercised options	1.0	5.0
Cash received from exercise of stock options (less than in 2018)	$ 1.0	$ 3.0
Maximum | Other Award Types
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized				3,800,000
Share-equivalents issued (in shares)	(925)
Number of shares available for grant (in shares)	3,799,075				0
2018 Plan | RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	4,000,000
Share-equivalents issued (in shares)	(360,999)
Number of shares available for grant (in shares)	0				1,437,435
2015 Plan | SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	87,310
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized			1,500,000.0
Purchase price per share equal to lesser of fair market value percentage			95.00%
Number of shares available for grant (in shares)	869,514
Nonemployee directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	7,980	12,488