RESTRICTED CASH AND INVESTMENTS (Details) $ in Thousands	Jul. 01, 2018 USD ($) security	Dec. 31, 2017 USD ($) security
Restricted Cash and Investments [Line Items]
Cash collateral held by insurance carriers	$ 22,726	$ 22,926
Cash and cash equivalents held in Trust	25,447	16,113
Investments held in Trust	166,424	171,752
Deferred compensation mutual funds	24,384	22,428
Other restricted cash and cash equivalents	409	6,012
Restricted cash and investments	239,390	239,231
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	315	1,324
Gross Unrealized Loss	(2,107)	(838)
Fair Value	164,632	172,238
Estimated fair value
Less than 12 months	109,004	73,392
12 months or more	19,285	20,600
Total	128,289	93,992
Unrealized losses
Less than 12 months	(1,431)	(445)
12 months or more	(676)	(393)
Total	$ (2,107)	$ (838)
Securities in unrealized loss positions, number of positions \| security	114	83
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	$ 164,632	$ 172,238
Municipal debt securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	78,675	82,770
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	304	974
Gross Unrealized Loss	(789)	(378)
Fair Value	78,190	83,366
Estimated fair value
Less than 12 months	37,263	23,078
12 months or more	9,329	9,631
Total	46,592	32,709
Unrealized losses
Less than 12 months	(350)	(124)
12 months or more	(439)	(254)
Total	(789)	(378)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	78,190	83,366
Corporate debt securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	83,481	83,916
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	5	309
Gross Unrealized Loss	(1,248)	(434)
Fair Value	82,238	83,791
Estimated fair value
Less than 12 months	69,369	48,952
12 months or more	8,980	10,081
Total	78,349	59,033
Unrealized losses
Less than 12 months	(1,042)	(311)
12 months or more	(206)	(123)
Total	(1,248)	(434)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	82,238	83,791
Agency mortgage-backed securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	3,269	4,066
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	6	22
Gross Unrealized Loss	(46)	(26)
Fair Value	3,229	4,062
Estimated fair value
Less than 12 months	1,397	1,362
12 months or more	976	888
Total	2,373	2,250
Unrealized losses
Less than 12 months	(15)	(10)
12 months or more	(31)	(16)
Total	(46)	(26)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	3,229	4,062
U.S. government and agency securities
Restricted Cash and Investments [Line Items]
Investments held in Trust	999	1,000
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Gross Unrealized Gain	0	19
Gross Unrealized Loss	(24)	0
Fair Value	975	1,019
Estimated fair value
Less than 12 months	975
12 months or more	0
Total	975
Unrealized losses
Less than 12 months	(24)
12 months or more	0
Total	(24)
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Fair Value	975	$ 1,019
Restricted Cash and Investments [Member]
Restricted Cash and Investments [Line Items]
Investments held in Trust	166,424
Held-to-maturity Securities, Reconciliation to Fair Value [Abstract]
Fair Value	164,632
Held-to-maturity Securities, Investment Maturities, Amortized Cost [Abstract]
Due in one year or less	24,233
Due after one year through five years	91,941
Due after five years through ten years	50,250
Held-to-maturity Securities, Investment Maturities, Fair Value [Abstract]
Due in one year or less	24,101
Due after one year through five years	91,148
Due after five years through ten years	49,383
Fair Value	$ 164,632

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