Discontinued Operations - Unconsolidated Subsidiaries - Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Equity Method Investment, Summarized Financial Information [Abstract]
Gross profit	$ 380,024	$ 316,260	$ 246,081
Operating income	78,458	46,038	31,409
Net income	$ 64,853	437,416	116,464
ULVAC Cryogenics, Inc.
Equity Method Investment, Summarized Financial Information [Abstract]
Total revenue		88,357	94,652
Gross profit		35,127	34,982
Operating income		17,791	18,405
Net income		$ 12,483	$ 13,345