Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 30,925		$ 28,593
Equity in earnings of equity method investment	$ 2,180	$ 1,942
ULVAC Cryogenics, Inc.
Schedule of Equity Method Investments [Line Items]
Joint venture interest (as a percent)	50.00%
Equity method investment	$ 30,900		$ 28,600
Equity in earnings of equity method investment	2,200	2,400
Management fee payments received	$ 300	$ 300