Discontinued Operations - Financial Results (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent, Total	$ 8,149	$ 14,867
Discontinued Operations, Held-for-sale | Semiconductor Cryogenics Business
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue	39,324	46,729
Total cost of revenue	22,565	25,773
Gross profit	16,759	20,956
Research and development	2,158	1,794
Selling, general and administrative	7,203	3,247
Total operating expenses	9,361	5,041
Operating income	7,398	15,915
Other (expense) income, net	289	272
Income before income taxes and earnings of equity method investment	7,687	16,187
Income tax provision	1,310	3,500
Income before equity in earnings of equity method investment	6,377	12,687
Equity in earnings of equity method investment	1,772	2,180
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent, Total	8,149	14,867
Discontinued Operations, Held-for-sale | Semiconductor Cryogenics Business | Products
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue	28,786	36,412
Total cost of revenue	16,516	20,648
Discontinued Operations, Held-for-sale | Semiconductor Cryogenics Business | Services
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total revenue	10,538	10,317
Total cost of revenue	$ 6,049	$ 5,125