BUSINESS SEGMENTS - Summary of Segment Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Continuing assets	$ 2,544,361	$ 2,439,942
Assets of discontinued operations	4,302	8,497
Total Assets	2,548,663	2,448,439
Operating Segments
Segment Reporting Information [Line Items]
Continuing assets	2,283,858	2,191,040
Operating Segments | Consumer and Professional Products
Segment Reporting Information [Line Items]
Continuing assets	1,375,959	1,255,127
Operating Segments | Home and Building Products
Segment Reporting Information [Line Items]
Continuing assets	627,704	606,785
Operating Segments | Defense Electronics
Segment Reporting Information [Line Items]
Continuing assets	280,195	329,128
Corporate
Segment Reporting Information [Line Items]
Continuing assets	$ 260,503	$ 248,902