GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($) reporting_unit	Sep. 30, 2019 USD ($)
Goodwill [Line Items]
Accumulated goodwill impairment loss			$ 178,732	$ 178,732
Number of reporting units | reporting_unit				2
Goodwill write-down	$ 90,408	$ 77,600	0	$ 90,408	$ 77,572
Amortization expense on intangible assets			84,233	71,514	$ 45,756
Future amortization expense [Abstract]
Future amortization expense 2022			57,569
Future amortization expense 2023			41,064
Future amortization expense 2024			35,505
Future amortization expense 2025			19,711
Future amortization expense 2026			$ 14,686
Graphics Imaging
Goodwill [Line Items]
Percent of fair value exceeding carrying value			5.00%
SGK Brand Solutions
Goodwill [Line Items]
Accumulated goodwill impairment loss			$ 173,732	173,732
Goodwill write-down				90,408
Memorialization
Goodwill [Line Items]
Accumulated goodwill impairment loss			$ 5,000	5,000
Goodwill write-down				$ 0