BUSINESS SEGMENTS - Income Before Taxes From Continuing Operations (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Segment operating profit:		$ 25,721	$ 16,886	$ 55,013	$ 31,041
Net interest expense		(17,305)	(16,044)	(33,636)	(32,686)
Unallocated amounts		(11,347)	(10,541)	(22,745)	(20,977)
Acquisition costs		0
Cost of life insurance benefit	$ (13,715)
Income before taxes from continuing operations		9,684	3,188	23,649	1,115
Postretirement Life Insurance [Member] \| Continuing Operations [Member]
Segment Reporting Information [Line Items]
Segment operating profit from continuing operations		38,336	29,780	80,030	59,011
Net interest expense		(17,305)	(16,044)	(33,636)	(32,686)
Unallocated amounts		(11,347)	(10,541)	(22,745)	(20,977)
Acquisition costs		0	(7)	0	(1,619)
Cost of life insurance benefit		0	0	0	(2,614)
Income before taxes from continuing operations		9,684	3,188	23,649	1,115
Postretirement Life Insurance [Member] \| Continuing Operations [Member] \| Home And Building Products [Member]
Segment Reporting Information [Line Items]
Segment operating profit:		36,021	28,478	75,566	56,229
Postretirement Life Insurance [Member] \| Continuing Operations [Member] \| Telephonics [Member]
Segment Reporting Information [Line Items]
Segment operating profit:		$ 2,315	$ 1,302	$ 4,464	$ 2,782

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Amount of unallocated expense included in noninterest expense for the reportable segment during the period.

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- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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- Definition

Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement.

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-Publisher FASB
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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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The net amount of operating interest income (expense).

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The net result for the period of deducting operating expenses from operating revenues.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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