BUSINESS SEGMENTS - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 632,061	$ 574,970	$ 1,746,849	$ 1,635,125
United States
Disaggregation of Revenue [Line Items]
Revenue	498,060	449,816	1,376,854	1,282,423
Europe
Disaggregation of Revenue [Line Items]
Revenue	37,984	34,081	85,219	81,136
Canada
Disaggregation of Revenue [Line Items]
Revenue	28,972	28,968	90,171	90,830
Australia
Disaggregation of Revenue [Line Items]
Revenue	48,626	36,830	142,681	124,656
All other countries
Disaggregation of Revenue [Line Items]
Revenue	18,419	25,275	51,924	56,080
Consumer and Professional Products
Disaggregation of Revenue [Line Items]
Revenue	328,929	273,710	844,917	777,916
Consumer and Professional Products | United States
Disaggregation of Revenue [Line Items]
Revenue	232,544	193,948	584,114	541,309
Consumer and Professional Products | Europe
Disaggregation of Revenue [Line Items]
Revenue	29,267	25,663	60,609	53,871
Consumer and Professional Products | Canada
Disaggregation of Revenue [Line Items]
Revenue	18,231	16,246	53,527	54,456
Consumer and Professional Products | Australia
Disaggregation of Revenue [Line Items]
Revenue	47,614	35,829	140,874	121,617
Consumer and Professional Products | All other countries
Disaggregation of Revenue [Line Items]
Revenue	1,273	2,024	5,793	6,663
Consumer and Professional Products | Residential repair and remodel
Disaggregation of Revenue [Line Items]
Revenue	50,709	35,416	126,304	101,015
Consumer and Professional Products | Retail
Disaggregation of Revenue [Line Items]
Revenue	177,271	148,596	441,795	424,537
Consumer and Professional Products | Residential new construction
Disaggregation of Revenue [Line Items]
Revenue	14,487	15,345	44,344	43,162
Consumer and Professional Products | Industrial
Disaggregation of Revenue [Line Items]
Revenue	9,303	12,880	30,461	34,054
Consumer and Professional Products | International excluding North America
Disaggregation of Revenue [Line Items]
Revenue	77,159	61,473	202,013	175,148
Home and Building Products
Disaggregation of Revenue [Line Items]
Revenue	219,164	221,521	670,374	631,615
Home and Building Products | United States
Disaggregation of Revenue [Line Items]
Revenue	209,222	206,489	635,232	592,261
Home and Building Products | Europe
Disaggregation of Revenue [Line Items]
Revenue	81	31	109	77
Home and Building Products | Canada
Disaggregation of Revenue [Line Items]
Revenue	7,729	9,867	26,849	27,832
Home and Building Products | Australia
Disaggregation of Revenue [Line Items]
Revenue	0	163	0	613
Home and Building Products | All other countries
Disaggregation of Revenue [Line Items]
Revenue	2,132	4,971	8,184	10,832
Home and Building Products | Residential repair and remodel
Disaggregation of Revenue [Line Items]
Revenue	109,876	112,730	332,681	316,368
Home and Building Products | Commercial construction
Disaggregation of Revenue [Line Items]
Revenue	84,521	83,382	262,708	243,939
Home and Building Products | Residential new construction
Disaggregation of Revenue [Line Items]
Revenue	24,767	25,409	74,985	71,308
Defense Electronics
Disaggregation of Revenue [Line Items]
Revenue	83,968	79,739	231,558	225,594
Defense Electronics | United States
Disaggregation of Revenue [Line Items]
Revenue	56,294	49,379	157,508	148,853
Defense Electronics | Europe
Disaggregation of Revenue [Line Items]
Revenue	8,636	8,387	24,501	27,188
Defense Electronics | Canada
Disaggregation of Revenue [Line Items]
Revenue	3,012	2,855	9,795	8,542
Defense Electronics | Australia
Disaggregation of Revenue [Line Items]
Revenue	1,012	838	1,807	2,426
Defense Electronics | All other countries
Disaggregation of Revenue [Line Items]
Revenue	15,014	18,280	37,947	38,585
Defense Electronics | U.S. Government
Disaggregation of Revenue [Line Items]
Revenue	54,802	46,579	151,126	138,515
Defense Electronics | International
Disaggregation of Revenue [Line Items]
Revenue	24,779	30,120	68,333	75,348
Defense Electronics | Commercial
Disaggregation of Revenue [Line Items]
Revenue	$ 4,387	$ 3,040	$ 12,099	$ 11,731