Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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Fair value portion of assets, excluding financial assets, that lack physical substance, having a limited useful life.

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Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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FAIR VALUE MEASUREMENT (Details) - USD ($) $ in Thousands	12 Months Ended
FAIR VALUE MEASUREMENT (Details) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018	Mar. 29, 2020	Dec. 31, 2017
Total Fair Value
Fair Value Measurement [Line Items]
Cash and cash equivalents	$ 62,507	$ 37,608
Total Fair Value \| Restricted Assets
Fair Value Measurement [Line Items]
Restricted cash and cash equivalents	56,105	54,763
Cash, cash equivalents and restricted cash	118,612	92,371
Restricted investments classified as held-to-maturity	158,296	152,731
Deferred compensation investments	5,915	13,670
Total Fair Value \| Restricted Assets \| Municipal debt securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	70,723	74,236
Total Fair Value \| Restricted Assets \| Corporate debt securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	85,937	76,068
Total Fair Value \| Restricted Assets \| Agency mortgage-backed securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	512	1,376
Total Fair Value \| Restricted Assets \| U.S. government and agency securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	1,124	1,051
Total Fair Value \| Fair Value, Nonrecurring [Member]
Fair Value Measurement [Line Items]
Goodwill and intangible assets				$ 46,405
Goodwill, fair value				31,705
Finite-lived intangible assets, fair value				14,700
Cash, cash equivalents and restricted cash	118,612	92,371	$ 102,450		$ 73,831
Restricted investments classified as held-to-maturity	158,296	152,731
Deferred compensation investments	5,915	13,670
Goodwill and intangible asset impairment charge	(175,189)	0	$ 0
Goodwill, impairment charge	(140,489)
Impairment of finite-lived intangible assets	(34,700)
Municipal debt securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	70,723	74,236
Corporate debt securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	85,937	76,068
Agency mortgage-backed securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	512	1,376
U.S. government and agency securities
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	1,124	1,051
Restricted Assets \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Cash, cash equivalents and restricted cash	118,612	92,371
Restricted investments classified as held-to-maturity	0	0
Restricted Assets \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Cash, cash equivalents and restricted cash	0	0
Restricted investments classified as held-to-maturity	158,296	152,731
Restricted Assets \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Cash, cash equivalents and restricted cash	0	0
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Cash and cash equivalents	62,507	37,608
Fair Value, Recurring \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Cash and cash equivalents	0	0
Fair Value, Recurring \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Cash and cash equivalents	0	0
Fair Value, Recurring \| Restricted Assets \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Restricted cash and cash equivalents	56,105	54,763
Deferred compensation investments	5,915	13,670
Fair Value, Recurring \| Restricted Assets \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Restricted cash and cash equivalents	0	0
Deferred compensation investments	0	0
Fair Value, Recurring \| Restricted Assets \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Restricted cash and cash equivalents	0	0
Deferred compensation investments	0	0
Fair Value, Recurring \| Restricted Assets \| Municipal debt securities \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| Municipal debt securities \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	70,723	74,236
Fair Value, Recurring \| Restricted Assets \| Municipal debt securities \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| Corporate debt securities \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| Corporate debt securities \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	85,937	76,068
Fair Value, Recurring \| Restricted Assets \| Corporate debt securities \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| Agency mortgage-backed securities \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| Agency mortgage-backed securities \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	512	1,376
Fair Value, Recurring \| Restricted Assets \| Agency mortgage-backed securities \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| U.S. government and agency securities \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	0
Fair Value, Recurring \| Restricted Assets \| U.S. government and agency securities \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	1,124	1,051
Fair Value, Recurring \| Restricted Assets \| U.S. government and agency securities \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Restricted investments classified as held-to-maturity	0	$ 0
Fair Value, Nonrecurring [Member]
Fair Value Measurement [Line Items]
Goodwill and intangible assets				221,600
Goodwill and intangible asset impairment charge	(175,189)
Goodwill, impairment charge	(140,489)
Impairment of finite-lived intangible assets	$ (34,700)
Fair Value, Nonrecurring [Member] \| Quoted prices in active markets for identical assets (level 1)
Fair Value Measurement [Line Items]
Goodwill and intangible assets				0
Goodwill, fair value				0
Finite-lived intangible assets, fair value				0
Fair Value, Nonrecurring [Member] \| Significant other observable inputs (level 2)
Fair Value Measurement [Line Items]
Goodwill and intangible assets				0
Goodwill, fair value				0
Finite-lived intangible assets, fair value				0
Fair Value, Nonrecurring [Member] \| Significant unobservable inputs (level 3)
Fair Value Measurement [Line Items]
Goodwill and intangible assets				46,405
Goodwill, fair value				31,705
Finite-lived intangible assets, fair value				$ 14,700