Equity Method Investments - ULVAC Cryogenics, Inc. (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 32,628		$ 32,628		$ 27,273
Equity in earnings of equity method investments	$ 2,530	$ 379	$ 7,249	$ 1,248
Ulvac Cryogenics Incorporated
Schedule of Equity Method Investments [Line Items]
Joint venture interest, percentage	50.00%		50.00%
Equity method investments	$ 32,600		$ 32,600		25,600
Equity in earnings of equity method investments	2,500	700	7,700	2,000
Management fee payments received	300	$ 200	800	600
Charges incurred from related parties			200	$ 200
Accounts payable for unpaid products and services (less than)	$ 100		$ 100		$ 100