FAIR VALUE MEASUREMENT Changes in Fair Value of Recurring Fair Value Measurements Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands | Apr. 01, 2018 | Dec. 31, 2017 | Apr. 02, 2017 | Jan. 01, 2017 |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Cash, cash equivalents and restricted cash | $ 79,054 | $ 73,831 | $ 80,439 | $ 103,222 |
Deferred compensation mutual funds | 24,093 | 22,428 | | |
Held-to-maturity Securities, Fair Value | 164,446 | 172,238 | | |
Total Fair Value | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Cash and cash equivalents | 26,636 | 28,780 | | |
Significant Unobservable Inputs (Level 3) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Cash and cash equivalents | 0 | 0 | | |
Significant Other Observable Inputs (Level 2) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Cash and cash equivalents | 0 | 0 | | |
Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Cash and cash equivalents | 26,636 | 28,780 | | |
Restricted Assets | Total Fair Value | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Restricted cash and cash equivalents | 52,418 | 45,051 | | |
Cash, cash equivalents and restricted cash | 79,054 | 73,831 | | |
Deferred compensation mutual funds | 24,093 | 22,428 | | |
Held-to-maturity Securities, Fair Value | 164,446 | 172,238 | | |
Restricted Assets | Significant Unobservable Inputs (Level 3) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Restricted cash and cash equivalents | 0 | 0 | | |
Cash, cash equivalents and restricted cash | 0 | 0 | | |
Deferred compensation mutual funds | 0 | 0 | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Restricted Assets | Significant Other Observable Inputs (Level 2) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Restricted cash and cash equivalents | 0 | 0 | | |
Cash, cash equivalents and restricted cash | 0 | 0 | | |
Deferred compensation mutual funds | 0 | 0 | | |
Held-to-maturity Securities, Fair Value | 164,446 | 172,238 | | |
Restricted Assets | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Restricted cash and cash equivalents | 52,418 | 45,051 | | |
Cash, cash equivalents and restricted cash | 79,054 | 73,831 | | |
Deferred compensation mutual funds | 24,093 | 22,428 | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Municipal debt securities | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 78,643 | 83,366 | | |
Municipal debt securities | Restricted Assets | Total Fair Value | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 78,643 | 83,366 | | |
Municipal debt securities | Restricted Assets | Significant Unobservable Inputs (Level 3) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Municipal debt securities | Restricted Assets | Significant Other Observable Inputs (Level 2) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 78,643 | 83,366 | | |
Municipal debt securities | Restricted Assets | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Corporate debt securities | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 81,182 | 83,791 | | |
Corporate debt securities | Restricted Assets | Total Fair Value | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 81,182 | 83,791 | | |
Corporate debt securities | Restricted Assets | Significant Unobservable Inputs (Level 3) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Corporate debt securities | Restricted Assets | Significant Other Observable Inputs (Level 2) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 81,182 | 83,791 | | |
Corporate debt securities | Restricted Assets | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Agency mortgage-backed securities | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 3,630 | 4,062 | | |
Agency mortgage-backed securities | Restricted Assets | Total Fair Value | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 3,630 | 4,062 | | |
Agency mortgage-backed securities | Restricted Assets | Significant Unobservable Inputs (Level 3) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
Agency mortgage-backed securities | Restricted Assets | Significant Other Observable Inputs (Level 2) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 3,630 | 4,062 | | |
Agency mortgage-backed securities | Restricted Assets | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
U.S. government and agency securities | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 991 | 1,019 | | |
U.S. government and agency securities | Restricted Assets | Total Fair Value | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 991 | 1,019 | | |
U.S. government and agency securities | Restricted Assets | Significant Unobservable Inputs (Level 3) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 0 | 0 | | |
U.S. government and agency securities | Restricted Assets | Significant Other Observable Inputs (Level 2) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | 991 | 1,019 | | |
U.S. government and agency securities | Restricted Assets | Quoted Prices in Active Markets for Identical Assets (Level 1) | | | | |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] | | | | |
Held-to-maturity Securities, Fair Value | $ 0 | $ 0 | | |