Income Taxes - Tax Jurisdictions and Years Currently under Audit Exam (Details)	6 Months Ended
	Mar. 31, 2021
UNITED STATES | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2017
UNITED STATES | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2018
BELGIUM | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2015
BELGIUM | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2020
CHINA | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2017
CHINA | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2019
Germany | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2007
Germany | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2018
LUXEMBOURG | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2017
LUXEMBOURG | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2018
MEXICO | Earliest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2015
MEXICO | Latest tax year under exam
Income Tax Examination [Line Items]
Tax years currently under audit exam	2020
TAIWAN, PROVINCE OF CHINA
Income Tax Examination [Line Items]
Tax years currently under audit exam	2019
United Kingdom | Tax Year 2014
Income Tax Examination [Line Items]
Tax years currently under audit exam	2014
United Kingdom | Tax Year 2015 [Member]
Income Tax Examination [Line Items]
Tax years currently under audit exam	2015
United Kingdom | Tax Year 2018
Income Tax Examination [Line Items]
Tax years currently under audit exam	2018