REVENUE - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Oct. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of performance obligations recognized at a point in time (more than)		80.00%
Percentage of performance obligations recognized over time (less than)		20.00%
Favorable (unfavorable) catch-up adjustments to income from operations		$ (4,500)	$ 1,400	$ 600
Accumulated estimated costs to complete loss contracts		9,800
Contract costs and recognized income not yet billed, net of progress payments, current		105,111	121,803		$ 100,821
Decrease in contract assets balance		16,692
Contract costs and recognized income not yet billed, net of progress payments, noncurrent		13,100	29,500
Unbilled receivable reserve		0	400
Billings in excess of costs		26,259			25,841
Increase in billings in excess of costs		8,700
Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustment for new accounting pronouncement	[1]				5,618
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract costs and recognized income not yet billed, net of progress payments, current		119,348	121,803
Billings in excess of costs		$ 17,977	$ 17,559
Retained Earnings [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustment for new accounting pronouncement	[1]				$ 5,618
Minimum [Member] | Construction and Professional Products and Home and Building Products Segments [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment term		15 days
Maximum [Member] | Construction and Professional Products and Home and Building Products Segments [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment term		90 days

[1] See Note 1 - Recently adopted accounting pronouncements and Note 2 - Revenue for additional information.