FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Measurements, Recurring $ in Thousands, £ in Millions	Dec. 24, 2021 GBP (£)	Dec. 24, 2021 USD ($)	Sep. 30, 2021 GBP (£)	Sep. 30, 2021 USD ($)
Assets
Forward currency contracts | £	£ 37.4		£ 37.4
Level 1
Assets
Cash equivalents		$ 314,155		$ 489,987
Forward currency contracts		0		0
Liabilities
Forward currency contracts		0		0
Level 2
Assets
Cash equivalents		0		0
Forward currency contracts		304		127
Liabilities
Forward currency contracts		$ 163		$ 183