Basis of Presentation - Discontinued Operations (Details) - Semiconductor Cryogenics Business - USD ($) $ in Thousands	Jul. 01, 2019	Sep. 30, 2018	Aug. 27, 2018	Sep. 30, 2017
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration	$ 661,500
Net working capital adjustments	6,300
Net cash proceeds from the sale	$ 553,100
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration			$ 675,000
Disposal Group, Including Discontinued Operation, Accounts Payable and Accrued Liabilities, Current [Abstract]
Accounts payable		$ 11,149		$ 10,600