DEFINED BENEFIT RETIREMENT PLAN (Details) £ in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2017 GBP (£) item	Dec. 30, 2017 USD ($) item $ / £	Dec. 31, 2016 USD ($) $ / £	Dec. 26, 2015 USD ($)
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Pension retirement benefits to qualified employees as percent of final salary per year of service	1.67%	1.67%
Eligibility age	65 years	65 years
Active members of defined benefit retirement income plan | item	0	0
Foreign currency exchange rate used to translate the net pension liability | $ / £		1.3490	1.2340
Defined benefit pension liability		$ 189,552	$ 209,470
Change in Projected Benefit Obligation
Beginning balance		696,137	697,449
Interest cost		18,152	23,496
Benefits paid		(22,172)	(17,792)
Actuarial loss			(125,765)
Ending balance		783,301	696,137
Plan Assets
Fair value beginning balance		486,667	518,126
Employer contributions		40,245	1,426
Actual return on plan assets		40,842	80,538
Benefits paid		(22,172)	(17,792)
Currency translation		48,167	(95,631)
Fair value ending balance		593,749	486,667
Funded status
Funded status		(189,552)	(209,470)	$ (179,323)
Accumulated other comprehensive income (loss)
Balance at the beginning of the period		(156,878)	(106,959)
Actuarial loss		(1,789)	(66,957)
Currency translation gain (loss)		(9,583)	17,038
Balance at the end of the period		$ (168,250)	$ (156,878)
Weighted average actuarial assumptions used to determine the benefit obligation
Discount rate (as a percent)		2.55%	2.80%
CPI index (as a percent)		2.20%	2.25%
RPI Inflation (as a percent)		3.30%	3.15%
Net periodic benefit expense:
Interest cost		$ 18,152	$ 23,496
Expected return on plan assets		(20,486)	(22,986)
Defined Benefit Plan, Amortization of Gains (Losses)		(2,982)	(1,360)
Net periodic benefit expense		$ 648	$ 1,870
Weighted average actuarial assumptions used to determine expense
Discount rate (as a percent)	2.80%	2.80%	3.75%
Expected return on plan assets (as a percent)	4.22%	4.22%	5.15%
RPI index (as a percent)	2.25%	2.25%	2.15%
CPI index (as a percent)	3.35%	3.35%	3.35%
Limit on employer contributions per annum	£ 10,000	$ 13,490
Administrative costs of the Plan	£ 1,100	1,484
Expected pension benefit payments
2016		23,879
2017		24,689
2018		25,500
2019		26,308
2020		27,117
2021-2025		$ 149,078
Weighted average maturity period of corporate bond portfolio	13 years	13 years
Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss)		$ 66,030	$ (132,781)