v3.26.1
FAIR VALUE - Asset Measured at Fair Value (Details)
$ in Thousands
3 Months Ended
Mar. 28, 2026
USD ($)
item
Dec. 27, 2025
USD ($)
FAIR VALUE    
Number of investments fully impaired | item 1  
Impairment of investments $ 4,000  
Money market funds | Cash and cash equivalents    
FAIR VALUE    
Investments at fair value 108,300 $ 207,900
Money market funds | Restricted investments    
FAIR VALUE    
Investments at fair value 800 600
Fixed income funds | Restricted investments    
FAIR VALUE    
Investments at fair value 55,500 49,900
Equity securities | Other assets    
FAIR VALUE    
Investments at fair value 24,700 28,000
Mutual funds, equity and alternative investments | Investments    
FAIR VALUE    
Investments at fair value 35,000 34,300
Money market and mutual funds | Other assets    
FAIR VALUE    
Investments at fair value 200 200
Prices with Unobservable Inputs (Level 3) | Equity securities | Other assets    
FAIR VALUE    
Investments at fair value 24,700 28,000
Ardellis Insurance Ltd.    
FAIR VALUE    
Total fair value 90,548 84,271
Estimate of Fair Value Measurement | Recurring    
FAIR VALUE    
Investments at fair value 224,512 320,875
Estimate of Fair Value Measurement | Recurring | Money market funds    
FAIR VALUE    
Investments at fair value 109,126 208,501
Estimate of Fair Value Measurement | Recurring | Fixed income funds    
FAIR VALUE    
Investments at fair value 55,184 49,592
Estimate of Fair Value Measurement | Recurring | Treasury securities    
FAIR VALUE    
Investments at fair value 346 345
Estimate of Fair Value Measurement | Recurring | Equity securities    
FAIR VALUE    
Investments at fair value 44,084 46,492
Estimate of Fair Value Measurement | Recurring | Alternative investments    
FAIR VALUE    
Investments at fair value 4,280 4,186
Estimate of Fair Value Measurement | Recurring | Mutual funds    
FAIR VALUE    
Investments at fair value 11,492 11,759
Estimate of Fair Value Measurement | Recurring | Domestic stock funds    
FAIR VALUE    
Investments at fair value 10,138 10,436
Estimate of Fair Value Measurement | Recurring | International stock funds    
FAIR VALUE    
Investments at fair value 836 816
Estimate of Fair Value Measurement | Recurring | Target funds    
FAIR VALUE    
Investments at fair value 11 11
Estimate of Fair Value Measurement | Recurring | Bond funds    
FAIR VALUE    
Investments at fair value 6 6
Estimate of Fair Value Measurement | Recurring | Alternative funds    
FAIR VALUE    
Investments at fair value 501 490
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1)    
FAIR VALUE    
Investments at fair value 112,692 218,012
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Money market funds    
FAIR VALUE    
Investments at fair value 76,143 182,051
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Fixed income funds    
FAIR VALUE    
Investments at fair value 5,361 5,365
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Treasury securities    
FAIR VALUE    
Investments at fair value 346 345
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Equity securities    
FAIR VALUE    
Investments at fair value 19,350 18,492
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Mutual funds    
FAIR VALUE    
Investments at fair value 11,492 11,759
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Domestic stock funds    
FAIR VALUE    
Investments at fair value 10,138 10,436
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | International stock funds    
FAIR VALUE    
Investments at fair value 836 816
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Target funds    
FAIR VALUE    
Investments at fair value 11 11
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Bond funds    
FAIR VALUE    
Investments at fair value 6 6
Estimate of Fair Value Measurement | Recurring | Quoted Prices in Active Markets (Level 1) | Alternative funds    
FAIR VALUE    
Investments at fair value 501 490
Estimate of Fair Value Measurement | Recurring | Prices with Other Observable Inputs (Level 2)    
FAIR VALUE    
Investments at fair value 82,806 70,677
Estimate of Fair Value Measurement | Recurring | Prices with Other Observable Inputs (Level 2) | Money market funds    
FAIR VALUE    
Investments at fair value 32,983 26,450
Estimate of Fair Value Measurement | Recurring | Prices with Other Observable Inputs (Level 2) | Fixed income funds    
FAIR VALUE    
Investments at fair value 49,823 44,227
Estimate of Fair Value Measurement | Recurring | Prices with Unobservable Inputs (Level 3)    
FAIR VALUE    
Investments at fair value 29,014 32,186
Estimate of Fair Value Measurement | Recurring | Prices with Unobservable Inputs (Level 3) | Equity securities    
FAIR VALUE    
Investments at fair value 24,734 28,000
Estimate of Fair Value Measurement | Recurring | Prices with Unobservable Inputs (Level 3) | Alternative investments    
FAIR VALUE    
Investments at fair value $ 4,280 $ 4,186