Acquisitions - Amounts of Assets and Liabilities at Fair Value as of Acquisition Date (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Apr. 20, 2018	Apr. 06, 2018	Oct. 05, 2017	Sep. 30, 2017
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	$ 282,205				$ 233,638
BioSpeciMan Corporation
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable		$ 300
Intangible assets, finite-lived		2,600
Goodwill		2,700
Assumed liabilities		700
Total purchase price		$ 5,200
Tec-Sem Group AG
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable			$ 988
Inventories			4,297
Prepaid expenses and other current assets			4,038
Property, plant and equipment			85
Intangible assets, finite-lived			10,694
Goodwill			7,573
Accounts payable			(1,049)
Accrued liabilities			(6,962)
Deferred tax liabilities			(772)
Accrued pension liability			(3,328)
Noncontrolling interest			(987)
Total purchase price			$ 14,577
4titude Limited
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable				$ 1,581
Inventories				2,667
Prepaid expenses and other current assets				140
Property, plant and equipment				1,555
Intangible assets, finite-lived				27,212
Goodwill				38,185
Accounts payable				(286)
Accrued liabilities				(845)
Deferred tax liabilities				(5,090)
Total purchase price				$ 65,119