BUSINESS SEGMENTS - Summary of Segment Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Continuing assets	$ 2,517,460	$ 2,439,942
Assets of discontinued operations	6,820	8,497
Total Assets	2,524,280	2,448,439
Operating Segments
Segment Reporting Information [Line Items]
Continuing assets	2,300,889	2,191,040
Operating Segments | Consumer and Professional Products
Segment Reporting Information [Line Items]
Continuing assets	1,408,545	1,255,127
Operating Segments | Home and Building Products
Segment Reporting Information [Line Items]
Continuing assets	604,325	606,785
Operating Segments | Defense Electronics
Segment Reporting Information [Line Items]
Continuing assets	288,019	329,128
Corporate
Segment Reporting Information [Line Items]
Continuing assets	$ 216,571	$ 248,902