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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.

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