BUSINESS SEGMENTS - Summary of Segment Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Segment Reporting Information [Line Items]
Continuing assets	$ 2,477,455	$ 2,439,942
Assets of discontinued operations	6,988	8,497
Total Assets	2,484,443	2,448,439
Operating Segments
Segment Reporting Information [Line Items]
Continuing assets	2,204,502	2,191,040
Operating Segments | Consumer and Professional Products
Segment Reporting Information [Line Items]
Continuing assets	1,309,603	1,255,127
Operating Segments | Home and Building Products
Segment Reporting Information [Line Items]
Continuing assets	600,323	606,785
Operating Segments | Defense Electronics
Segment Reporting Information [Line Items]
Continuing assets	294,576	329,128
Corporate
Segment Reporting Information [Line Items]
Continuing assets	$ 272,953	$ 248,902