Reorganization and Realignment Costs G&A Realignment - May 2017 Plan Accrual Rollforward (Details) - G&A Realignment – May 2017 Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Restructuring Cost and Reserve
Beginning balance			$ 12,270	$ 0
Charges	$ 296	$ 1,851	4,847	15,402
Payments for Restructuring			(8,868)	(2,207)
Ending balance	8,249	13,195	8,249	13,195
Severance and related employee costs
Restructuring Cost and Reserve
Beginning balance			12,093	0
Charges	57	1,210	3,168	14,436
Payments for Restructuring			(7,103)	(1,350)
Ending balance	8,158	13,086	8,158	13,086
Recruitment and relocation costs
Restructuring Cost and Reserve
Beginning balance			177	0
Charges	200	145	708	145
Payments for Restructuring			(794)	(36)
Ending balance	91	109	91	109
Third-party and other costs
Restructuring Cost and Reserve
Beginning balance			0	0
Charges	39	496	971	821
Payments for Restructuring			(971)	(821)
Ending balance	0	$ 0	0	$ 0
Accrued expenses and other current liabilities
Restructuring Cost and Reserve
Ending balance	6,817		6,817
Other Liabilities
Restructuring Cost and Reserve
Ending balance	$ 1,432		$ 1,432