RESTRICTED CASH AND INVESTMENTS (Details) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($) security	Apr. 01, 2018 USD ($)	Dec. 30, 2018 USD ($) security
Restricted Cash and Investments [Line Items]
Cash collateral held by insurance carriers	$ 24,366		$ 24,182
Cash and cash equivalents held in Trust	30,354		28,021
Investments held in Trust	147,649		156,618
Deferred compensation mutual funds	26,969		23,363
Other restricted cash and cash equivalents	405		3,259
Restricted cash and investments	229,743		235,443
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	1,593		491
Gross Unrealized Loss	(424)		(1,468)
Fair Value	148,818		155,641
Estimated fair value
Less than 12 months	2,015		36,743
12 months or more	56,181		68,476
Total	58,196		105,219
Unrealized losses
Less than 12 months	(2)		(362)
12 months or more	(422)		(1,106)
Total	$ (424)		$ (1,468)
Securities in unrealized loss positions, number of positions \| security	54		93
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	$ 148,818		$ 155,641
Unrealized gain	2,400
Unrealized loss		$ (100)
Municipal debt securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	74,657		76,750
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	1,261		456
Gross Unrealized Loss	(124)		(516)
Fair Value	75,794		76,690
Estimated fair value
Less than 12 months	0		12,803
12 months or more	14,255		22,638
Total	14,255		35,441
Unrealized losses
Less than 12 months	0		(74)
12 months or more	(124)		(442)
Total	(124)		(516)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	75,794		76,690
Corporate debt securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	69,756		76,310
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	305		30
Gross Unrealized Loss	(284)		(908)
Fair Value	69,777		75,432
Estimated fair value
Less than 12 months	2,015		22,567
12 months or more	40,689		44,463
Total	42,704		67,030
Unrealized losses
Less than 12 months	(2)		(277)
12 months or more	(282)		(631)
Total	(284)		(908)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	69,777		75,432
Agency mortgage-backed securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	2,237		2,559
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	14		5
Gross Unrealized Loss	(16)		(33)
Fair Value	2,235		2,531
Estimated fair value
Less than 12 months	0		385
12 months or more	1,237		1,375
Total	1,237		1,760
Unrealized losses
Less than 12 months	0		0
12 months or more	(16)		(33)
Total	(16)		(33)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	2,235		2,531
U.S. government and agency securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	999		999
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	13		0
Gross Unrealized Loss	0		(11)
Fair Value	1,012		988
Estimated fair value
Less than 12 months			988
12 months or more			0
Total			988
Unrealized losses
Less than 12 months			(11)
12 months or more			0
Total			(11)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	1,012		$ 988
Restricted Cash and Investments
Restricted Cash and Investments [Line Items]
Investments held in Trust	147,649
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Fair Value	148,818
Held-to-maturity Securities, Investment Maturities, Amortized Cost [Abstract]
Due in one year or less	18,964
Due after one year through five years	86,051
Due after five years through ten years	42,634
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Due in one year or less	18,912
Due after one year through five years	86,524
Due after five years through ten years	43,382
Fair Value	$ 148,818

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