ACQUISITIONS AND DIVESTITURE TMP (Details) - USD ($) $ in Thousands		3 Months Ended								7 Months Ended	12 Months Ended
	Jun. 12, 2018	Dec. 30, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 30, 2018	Dec. 30, 2018	Dec. 31, 2017	Jan. 01, 2017
Business Acquisition [Line Items]
Cash purchase price, net of working capital adjustment											$ 22,742	$ 0	$ 72,476
Acquisition/integration costs											2,672	0	6,654
Goodwill		$ 237,287				$ 226,694				$ 237,287	237,287	226,694	224,223
Revenue from services		$ 650,147	$ 680,371	$ 614,301	$ 554,388	$ 669,625	$ 660,780	$ 610,122	$ 568,244		$ 2,499,207	$ 2,508,771	$ 2,750,640
TMP [Member]
Business Acquisition [Line Items]
Cash purchase price, net of working capital adjustment	$ 22,742
Cash Acquired from Acquisition	7,000
Acquisition/integration costs										2,700
Accounts receivable	9,770
Prepaid expenses, deposits and other current assets	337
Property and equipment	435
Intangible Assets	8,024
Total assets acquired	18,566
Accounts payable and other accrued expenses	9,139
Accrued wages and benefits	1,642
Income tax payable	205
Deferred income tax liability	1,444
Total liabilities assumed	12,430
Net identifiable assets acquired	6,136
Goodwill	16,606
Revenue from services										$ 31,000
Customer relationships | TMP [Member]
Business Acquisition [Line Items]
Intangible Assets	6,286
Trade name/trademarks | TMP [Member]
Business Acquisition [Line Items]
Intangible Assets	$ 1,738
Estimated useful life in years	14 years
Employer Branding [Member] | Customer relationships | TMP [Member]
Business Acquisition [Line Items]
Estimated useful life in years	3 years
RPO [Member] | Customer relationships | TMP [Member]
Business Acquisition [Line Items]
Estimated useful life in years	7 years