BUSINESS SEGMENTS - Segment EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 69,456	$ 53,068	$ 172,579	$ 140,930
Net interest expense	(16,585)	(17,087)	(49,096)	(50,723)
Depreciation and amortization	(15,523)	(15,595)	(47,067)	(46,172)
Loss from debt extinguishment	(1,235)	0	(7,925)	0
Income before taxes from continuing operations	34,480	20,386	54,360	44,035
Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA	80,536	65,101	207,548	175,435
Depreciation and amortization	(15,370)	(15,453)	(46,611)	(45,757)
Operating Segments | Consumer and Professional Products
Segment Reporting Information [Line Items]
Adjusted EBITDA	37,115	23,970	84,068	73,151
Depreciation and amortization	(8,197)	(8,158)	(24,650)	(24,148)
Operating Segments | Home and Building Products
Segment Reporting Information [Line Items]
Adjusted EBITDA	39,299	33,851	110,635	85,283
Depreciation and amortization	(4,507)	(4,626)	(13,975)	(13,683)
Operating Segments | Defense Electronics
Segment Reporting Information [Line Items]
Adjusted EBITDA	4,122	7,280	12,845	17,001
Depreciation and amortization	(2,666)	(2,669)	(7,986)	(7,926)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Adjusted EBITDA	(11,080)	(12,033)	(34,969)	(34,505)
Net interest expense	(16,585)	(17,087)	(49,096)	(50,723)
Depreciation and amortization	(15,523)	(15,595)	(47,067)	(46,172)
Loss from debt extinguishment	(1,235)	0	(7,925)	0
Restructuring charges	(1,633)	0	(11,171)	0
Acquisition costs	$ 0	$ 0	$ (2,960)	$ 0