DEFINED BENEFIT RETIREMENT PLAN (Details) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 27, 2014 USD ($) item	Dec. 27, 2014 GBP (£)	Dec. 28, 2013 USD ($)	Dec. 29, 2012 USD ($)
DEFINED BENEFIT RETIREMENT PLAN
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	0	0
Foreign currency exchange rate used to translate the net pension liability	1.5557		1.6469
Change in Projected Benefit Obligation
Beginning balance	$ 651,857		$ 597,767
Interest cost	28,667		26,431
Settlements			(12,981)
Benefits paid	(14,498)		(11,573)
Actuarial loss	66,889		37,235
Currency translation	40,632		14,978
Ending balance	692,283		651,857
Plan Assets
Fair value beginning balance	497,460		485,724
Employer contributions	18,173		17,619
Actual return on plan assets	72,820		7,676
Settlements			(12,981)
Benefits paid	(14,498)		(11,573)
Currency translation	(31,796)		10,995
Fair Value ending balance	542,159		497,460
Funded status
Funded status	(150,124)		(154,397)	(112,043)
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	(38,808)		12,617
Actuarial loss	(18,980)		(49,421)
Currency translation gain (loss)	1,835		(2,004)
Balance at the end of the period	(55,953)		(38,808)
The estimated amount to be amortized from accumulated other comprehensive income into net periodic benefit cost in 2015	0
Weighted average actuarial assumptions used to determine the benefit obligation
Discount rate (as a percent)	3.65%	3.65%	4.45%
CPI index (as a percent)	2.10%	2.10%	2.70%
RPI Inflation (as a percent)	3.20%	3.20%	3.60%
Net periodic benefit expense:
Interest cost	28,667		26,431
Expected return on plan assets	(26,029)		(19,862)
Net periodic benefit expense	2,638		6,569
Weighted average actuarial assumptions used to determine expense
Discount rate (as a percent)	4.45%	4.45%	4.60%
Expected return on plan assets (as a percent)	5.50%	5.50%	4.20%
RPI index (as a percent)	3.60%	3.60%	3.20%
CPI index (as a percent)	2.70%	2.70%	2.70%
Limit on employer contributions per annum	15,557	10,000
Administrative costs of the Plan	1,711	1,000
Expected pension benefit payments
2015	14,000
2016	14,500
2017	14,935
2018	15,400
2019	15,870
2020-2024	$ 86,341
Weighted average maturity period of corporate bond portfolio	13 years	13 years