Basis of Presentation - Discontinued Operations (Details) - Semiconductor Cryogenics Business - USD ($) $ in Thousands	Jul. 01, 2019	Jun. 30, 2019	Sep. 30, 2018	Aug. 27, 2018
Discontinued Operations, Disposed of by Sale | Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration	$ 675,000
Net cash proceeds from the sale, net of taxes and other items	$ 550,000
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		$ 8,511	$ 11,149