Employee Benefit Plans Employee Benefit Plans (Terminated Pension Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 195	$ 286
Assets used for settlements	0	91
Settlement loss recognized		21	$ 24,297
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions			9,500
Assets used for settlements			67,700
Service cost			100
Settlement loss recognized	$ 0	$ 0	$ 24,297