Employee Benefit Plans (Savings Plan) (Details) - USD ($) $ in Millions |
12 Months Ended | |
---|---|---|
Dec. 31, 2017 |
Jan. 01, 2017 |
|
Defined Benefit Plan Disclosure [Line Items] | ||
Defined Benefit Plan, 401(k) Savings Plan, Employer Contribution Match of Employees Eligible Compensation | 100.00% | |
Defined Benefit Plan, 401(k) Savings Plan, Maximum Employee Match Percent for Employer Match | 5.00% | |
Defined Benefit, 401(k) Savings Plan Expense | $ 12.5 | $ 12.8 |