FAIR VALUE - Asset Measured at Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 27, 2025	Dec. 27, 2025	Dec. 28, 2024
Fair Value
Impairment of investments	$ 6,500	$ 6,500
Money market funds \| Cash and cash equivalents
Fair Value
Investments at fair value	207,900	207,900	$ 377,400
Money market funds \| Restricted investments
Fair Value
Investments at fair value	600	600	400
Fixed income funds \| Restricted investments
Fair Value
Investments at fair value	49,900	49,900	38,700
Equity securities \| Other assets
Fair Value
Investments at fair value	28,000	28,000	26,000
Mutual funds, equity and alternative investments \| Investments
Fair Value
Investments at fair value	34,300	34,300	31,000
Money market and mutual funds \| Other assets
Fair Value
Investments at fair value	200	200	200
Prices with Unobservable Inputs (Level 3) \| Equity securities \| Other assets
Fair Value
Investments at fair value	28,000	28,000	26,000
Ardellis Insurance Ltd.
Fair Value
Total fair value	84,271	84,271	69,780
Estimate of Fair Value Measurement \| Recurring
Fair Value
Investments at fair value	320,875	320,875	473,685
Estimate of Fair Value Measurement \| Recurring \| Money market funds
Fair Value
Investments at fair value	208,501	208,501	377,850
Estimate of Fair Value Measurement \| Recurring \| Fixed income funds
Fair Value
Investments at fair value	49,592	49,592	38,348
Estimate of Fair Value Measurement \| Recurring \| Treasury securities
Fair Value
Investments at fair value	345	345	344
Estimate of Fair Value Measurement \| Recurring \| Equity securities
Fair Value
Investments at fair value	46,492	46,492	42,431
Estimate of Fair Value Measurement \| Recurring \| Alternative investments
Fair Value
Investments at fair value	4,186	4,186	4,044
Estimate of Fair Value Measurement \| Recurring \| Mutual funds
Fair Value
Investments at fair value	11,759	11,759	10,668
Estimate of Fair Value Measurement \| Recurring \| Domestic stock funds
Fair Value
Investments at fair value	10,436	10,436	9,534
Estimate of Fair Value Measurement \| Recurring \| International stock funds
Fair Value
Investments at fair value	816	816	641
Estimate of Fair Value Measurement \| Recurring \| Target funds
Fair Value
Investments at fair value	11	11	10
Estimate of Fair Value Measurement \| Recurring \| Bond funds
Fair Value
Investments at fair value	6	6	6
Estimate of Fair Value Measurement \| Recurring \| Alternative funds
Fair Value
Investments at fair value	490	490	477
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1)
Fair Value
Investments at fair value	218,012	218,012	389,415
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Money market funds
Fair Value
Investments at fair value	182,051	182,051	356,700
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Fixed income funds
Fair Value
Investments at fair value	5,365	5,365	5,272
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Treasury securities
Fair Value
Investments at fair value	345	345	344
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Equity securities
Fair Value
Investments at fair value	18,492	18,492	16,431
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Mutual funds
Fair Value
Investments at fair value	11,759	11,759	10,668
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Domestic stock funds
Fair Value
Investments at fair value	10,436	10,436	9,534
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| International stock funds
Fair Value
Investments at fair value	816	816	641
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Target funds
Fair Value
Investments at fair value	11	11	10
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Bond funds
Fair Value
Investments at fair value	6	6	6
Estimate of Fair Value Measurement \| Recurring \| Quoted Prices in Active Markets (Level 1) \| Alternative funds
Fair Value
Investments at fair value	490	490	477
Estimate of Fair Value Measurement \| Recurring \| Prices with Other Observable Inputs (Level 2)
Fair Value
Investments at fair value	70,677	70,677	54,226
Estimate of Fair Value Measurement \| Recurring \| Prices with Other Observable Inputs (Level 2) \| Money market funds
Fair Value
Investments at fair value	26,450	26,450	21,150
Estimate of Fair Value Measurement \| Recurring \| Prices with Other Observable Inputs (Level 2) \| Fixed income funds
Fair Value
Investments at fair value	44,227	44,227	33,076
Estimate of Fair Value Measurement \| Recurring \| Prices with Unobservable Inputs (Level 3)
Fair Value
Investments at fair value	32,186	32,186	30,044
Estimate of Fair Value Measurement \| Recurring \| Prices with Unobservable Inputs (Level 3) \| Equity securities
Fair Value
Investments at fair value	28,000	28,000	26,000
Estimate of Fair Value Measurement \| Recurring \| Prices with Unobservable Inputs (Level 3) \| Alternative investments
Fair Value
Investments at fair value	$ 4,186	$ 4,186	$ 4,044