Derivative Financial Instruments - Notional Amounts (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Interest rate swap contract
Derivative [Line Items]
Derivative notional amount	$ 560,003	$ 571,000
Foreign exchange contracts \| Buy
Derivative [Line Items]
Derivative notional amount	5,418	8,054
Foreign exchange contracts \| Sell
Derivative [Line Items]
Derivative notional amount	$ 27,725	$ 25,105

Nominal or face amount used to calculate payment on derivative.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant