REVENUE - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Oct. 01, 2018	Sep. 30, 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		$ (2,800)	$ (1,800)	$ (5,300)	$ (1,300)
Accumulated estimated costs to complete loss contracts		7,400		7,400			$ 12,200
Contract costs and recognized income not yet billed, net of progress payments, current		83,904		83,904		$ 100,821	121,803
Decrease in contract assets balance				37,899
Contract costs and recognized income not yet billed, net of progress payments, noncurrent		21,700		21,700			29,500
Unbilled receivable reserve		700		700			400
Billings in excess of costs		28,227		28,227		25,841
Increase in billings in excess of costs				10,668
Accounting Standards Update 2014-09 (ASC 606) [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustment for new accounting pronouncement	[1]					5,673
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		98,700		98,700			121,803
Billings in excess of costs		$ 19,945		$ 19,945			$ 17,559
Retained Earnings [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustment for new accounting pronouncement	[1]					5,673
Retained Earnings [Member] | Accounting Standards Update 2014-09 (ASC 606) [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect adjustment for new accounting pronouncement	[1]					$ 5,673
Minimum [Member] | Home And Building Products [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment term				15 days
Maximum [Member] | Home And Building Products [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment term				90 days

[1] See Note 14 - Recent Accounting Pronouncements and Note 3 - Revenue for additional information.