ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 26, 2021	Dec. 25, 2020	Mar. 27, 2020	Dec. 27, 2019	Mar. 26, 2021	Mar. 27, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 437,347	$ 378,410	$ 272,131	$ 232,936	$ 378,410	$ 232,936
Other comprehensive income before reclassifications	(818)		(6,229)		6,233	(1,120)
Amounts reclassified from accumulated other comprehensive loss, net of tax	262		226		524	433
Total other comprehensive income (loss)	(556)	7,313	(6,003)	5,316	6,757	(687)
Balance at end of period	570,162	437,347	295,434	272,131	570,162	295,434
Defined benefit pension items
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(30,499)	(30,761)	(23,611)	(23,818)	(30,761)	(23,818)
Other comprehensive income before reclassifications	0		0		0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax	262		226		524	433
Total other comprehensive income (loss)	262		226		524	433
Balance at end of period	(30,237)	(30,499)	(23,385)	(23,611)	(30,237)	(23,385)
Currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(4,742)	(11,793)	(12,771)	(17,880)	(11,793)	(17,880)
Other comprehensive income before reclassifications	(818)		(6,229)		6,233	(1,120)
Amounts reclassified from accumulated other comprehensive loss, net of tax	0		0		0	0
Total other comprehensive income (loss)	(818)		(6,229)		6,233	(1,120)
Balance at end of period	(5,560)	(4,742)	(19,000)	(12,771)	(5,560)	(19,000)
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(35,241)	(42,554)	(36,382)	(41,698)	(42,554)	(41,698)
Total other comprehensive income (loss)	(556)	7,313	(6,003)	5,316
Balance at end of period	$ (35,797)	$ (35,241)	$ (42,385)	$ (36,382)	$ (35,797)	$ (42,385)

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