Acquisitions and Divestitures (Memcor Divestiture) (Details) - USD ($) $ in Thousands				12 Months Ended
	Jan. 17, 2020	Dec. 31, 2019	Nov. 06, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets held for sale				$ 0	$ 37,256
Non-current assets held for sale				0	30,809
Current liabilities held for sale				0	14,208
Non-current liabilities held for sale				0	3,665
Gain on sale of business				(68,051)	$ 0	$ 0
Repayments of debt			$ 104,936
Memcor [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Businesses		$ 110,000
Payments for (Proceeds from) Businesses and Interest in Affiliates				131,011
Gain on sale of business				(57,700)
Payments to Employees				8,300
Business Acquisition, Transaction Costs				2,100
First Lien Term Loan, due December 20, 2024 | Memcor [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayments of debt	$ 100,000
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Memcor [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents				7,291
Receivables, net				9,603
Inventories, net				6,456
Contract assets				13,025
Prepaid and other current assets				881
Current assets held for sale				37,256
Property, plant and equipment, net				14,827
Goodwill				14,911
Intangible assets, net				1,024
Other non-current assets				47
Non-current assets held for sale				30,809
Total assets held for sale				68,065
Accounts payable				5,646
Contract liabilities				1,302
Product warranties				3,264
Accrued expenses and other liabilities				3,996
Current liabilities held for sale				14,208
Product warranties				1,594
Other non-current liabilities				2,071
Non-current liabilities held for sale				3,665
Total liabilities held for sale				$ 17,873