Discontinued Operations - Carrying Value of Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Oct. 01, 2018	Sep. 30, 2018
Disposal Group, Including Discontinued Operation, Assets [Abstract]
Total current assets of discontinued operation	$ 61,665		$ 66,148
Total long-term assets of discontinued operation	65,561		59,052
Disposal Group, Including Discontinued Operation, Liabilities [Abstract]
Total current liabilities of discontinued operation	12,741		18,537
Long-term liabilities of discontinued operation	107		698
Discontinued Operations, Held-for-sale | Semiconductor Cryogenics Business
Disposal Group, Including Discontinued Operation, Assets [Abstract]
Accounts receivable, net	22,812		27,852
Inventories	38,513		37,953
Other current assets	340		343
Total current assets of discontinued operation	61,665		66,148
Property, plant and equipment, net	1,320		1,081
Goodwill	26,484		26,485
Intangibles, net	15		14
Equity method investment	37,735		31,472
Other assets	7
Total long-term assets of discontinued operation	65,561		59,052
Disposal Group, Including Discontinued Operation, Liabilities [Abstract]
Accounts payable	8,511		11,149
Deferred revenue	1,126	$ 1,532	1,052
Accrued warranty and retrofit costs	2,555		2,464
Other current liabilities	549		3,872
Total current liabilities of discontinued operation	12,741		18,537
Long-term liabilities of discontinued operation	$ 107		$ 698