Employee Benefit Plan	12 Months Ended
Sep. 30, 2020
Deferred Compensation Arrangements [Abstract]
Employee Benefit Plan	13. Employee Benefit Plan We offer a savings plan to eligible U.S. employees. The plan is intended to qualify under Section 401(k) of the Internal Revenue Code. Participating employees may defer a portion of their pre-tax compensation, as defined, but not more than statutory limits. We contribute 50% of the amount contributed by the employee, up to a maximum of 3% of the employee’s earnings. Our matching contributions vest at a rate of 25% per year of service, with full vesting after 4 years of service. We made matching contributions of $6.7 million, $6.0 million, and $5.8 million in 2020, 2019 and 2018, respectively.

The entire disclosure for an entity's employee compensation and benefit plans, including, but not limited to, postemployment and postretirement benefit plans, defined benefit pension plans, defined contribution plans, non-qualified and supplemental benefit plans, deferred compensation, share-based compensation, life insurance, severance, health care, unemployment and other benefit plans.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-URI http://asc.fasb.org/topic&trid=2228938

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 712
-URI http://asc.fasb.org/topic&trid=2197446

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 710
-URI http://asc.fasb.org/topic&trid=2127225

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-URI http://asc.fasb.org/topic&trid=2235017

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