ACQUISITIONS Aon Purchase Price Allocation (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 04, 2016	Jan. 01, 2017	Dec. 25, 2015	Dec. 26, 2014
Business Acquisition [Line Items]
Cash purchase price, net of working capital adjustment (1)		$ 72,476	$ 67,500	$ 305,876
Goodwill		$ 224,223	$ 268,495	$ 241,855
Aon Hewitt
Business Acquisition [Line Items]
Cash purchase price, net of working capital adjustment (1)	$ 72,476
Accounts receivable	12,272
Prepaid expenses, deposits and other current assets	894
Intangible Assets	35,300
Total assets acquired	48,466
Accrued wages and benefits	1,025
Other long-term liabilities	456
Total liabilities assumed	1,481
Net identifiable assets acquired	46,985
Goodwill	$ 25,491
Goodwill, expected tax deductible amount, Period	15 years
Customer relationships | Aon Hewitt
Business Acquisition [Line Items]
Intangible Assets	$ 34,900
Technologies | Aon Hewitt
Business Acquisition [Line Items]
Intangible Assets	$ 400