FAIR VALUE MEASUREMENT (Details) - USD ($) $ in Thousands | Jul. 01, 2018 | Dec. 31, 2017 | Jul. 02, 2017 | Jan. 01, 2017 |
Fair Value Measurement [Line Items] | | | | |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents | $ 81,990 | $ 73,831 | $ 88,691 | $ 103,222 |
Deferred compensation mutual funds | 24,384 | 22,428 | | |
Restricted investments classified as held-to-maturity | 164,632 | 172,238 | | |
Municipal debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 78,190 | 83,366 | | |
Corporate debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 82,238 | 83,791 | | |
Agency mortgage-backed securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 3,229 | 4,062 | | |
U.S. government and agency securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 975 | 1,019 | | |
Total Fair Value | | | | |
Fair Value Measurement [Line Items] | | | | |
Cash and cash equivalents | 33,408 | 28,780 | | |
Total Fair Value | Restricted Assets | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted cash and cash equivalents | 48,582 | 45,051 | | |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents | 81,990 | 73,831 | | |
Deferred compensation mutual funds | 24,384 | 22,428 | | |
Restricted investments classified as held-to-maturity | 164,632 | 172,238 | | |
Total Fair Value | Restricted Assets | Municipal debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 78,190 | 83,366 | | |
Total Fair Value | Restricted Assets | Corporate debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 82,238 | 83,791 | | |
Total Fair Value | Restricted Assets | Agency mortgage-backed securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 3,229 | 4,062 | | |
Total Fair Value | Restricted Assets | U.S. government and agency securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 975 | 1,019 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value Measurement [Line Items] | | | | |
Cash and cash equivalents | 33,408 | 28,780 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Restricted Assets | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted cash and cash equivalents | 48,582 | 45,051 | | |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents | 81,990 | 73,831 | | |
Deferred compensation mutual funds | 24,384 | 22,428 | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Restricted Assets | Municipal debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Restricted Assets | Corporate debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Restricted Assets | Agency mortgage-backed securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Restricted Assets | U.S. government and agency securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Significant Other Observable Inputs (Level 2) | | | | |
Fair Value Measurement [Line Items] | | | | |
Cash and cash equivalents | 0 | 0 | | |
Significant Other Observable Inputs (Level 2) | Restricted Assets | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted cash and cash equivalents | 0 | 0 | | |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents | 0 | 0 | | |
Deferred compensation mutual funds | 0 | 0 | | |
Restricted investments classified as held-to-maturity | 164,632 | 172,238 | | |
Significant Other Observable Inputs (Level 2) | Restricted Assets | Municipal debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 78,190 | 83,366 | | |
Significant Other Observable Inputs (Level 2) | Restricted Assets | Corporate debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 82,238 | 83,791 | | |
Significant Other Observable Inputs (Level 2) | Restricted Assets | Agency mortgage-backed securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 3,229 | 4,062 | | |
Significant Other Observable Inputs (Level 2) | Restricted Assets | U.S. government and agency securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 975 | 1,019 | | |
Significant Unobservable Inputs (Level 3) | | | | |
Fair Value Measurement [Line Items] | | | | |
Cash and cash equivalents | 0 | 0 | | |
Significant Unobservable Inputs (Level 3) | Restricted Assets | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted cash and cash equivalents | 0 | 0 | | |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents | 0 | 0 | | |
Deferred compensation mutual funds | 0 | 0 | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Significant Unobservable Inputs (Level 3) | Restricted Assets | Municipal debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Significant Unobservable Inputs (Level 3) | Restricted Assets | Corporate debt securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Significant Unobservable Inputs (Level 3) | Restricted Assets | Agency mortgage-backed securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | 0 | 0 | | |
Significant Unobservable Inputs (Level 3) | Restricted Assets | U.S. government and agency securities | | | | |
Fair Value Measurement [Line Items] | | | | |
Restricted investments classified as held-to-maturity | $ 0 | $ 0 | | |