GOODWILL AND INTANGIBLE ASSETS - Amortized Intangible Assets - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 25, 2016	Jun. 27, 2015	Jun. 25, 2016	Jun. 27, 2015	Dec. 27, 2014	Dec. 26, 2015
Components of amortized intangible assets
Gross Carrying Amount	$ 212,585		$ 212,585			$ 215,939
Accumulated Amortization	117,867		117,867			111,672
Amortization expense for intangible assets	4,078	$ 4,737	8,073	$ 9,650
Estimated amortization expense
2015	15,906		15,906
2016	15,624		15,624
2017	13,990		13,990
2018	13,209		13,209
2019	12,158		12,158
Customer Relationships
Components of amortized intangible assets
Gross Carrying Amount	198,175		198,175			201,801
Accumulated Amortization	107,359		$ 107,359			101,614
Weighted Average Life			13 years		13 years
Proprietary Software & Database
Components of amortized intangible assets
Gross Carrying Amount	3,632		$ 3,632			3,571
Accumulated Amortization	3,031		$ 3,031			2,966
Weighted Average Life			8 years		8 years
Patents & Proprietary Technology
Components of amortized intangible assets
Gross Carrying Amount	6,922		$ 6,922			6,815
Accumulated Amortization	3,687		$ 3,687			3,421
Weighted Average Life			11 years		11 years
Other
Components of amortized intangible assets
Gross Carrying Amount	3,856		$ 3,856			3,752
Accumulated Amortization	$ 3,790		$ 3,790			$ 3,671
Weighted Average Life			3 years		3 years