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Description of the Company and Basis of Presentation (Details) shares in Thousands, $ in Thousands				3 Months Ended	6 Months Ended
	Feb. 11, 2021 shares	Dec. 04, 2020 shares	Oct. 29, 2018 segment	Mar. 31, 2021 segment	Mar. 31, 2021 USD ($) segment	Mar. 31, 2020 USD ($)
Subsidiary, Sale of Stock [Line Items]
Number of reportable segments \| segment			3	2	2
Net cash provided by operating activities					$ 63,058	$ 38,837
Net cash provided by financing activities					8,273	$ (108,327)
Reporting Of Tax Remittances For Certain Equity Awards \| Classification Error
Subsidiary, Sale of Stock [Line Items]
Classification error, amount					18,669
Reporting Of Tax Remittances For Certain Equity Awards \| Understatement
Subsidiary, Sale of Stock [Line Items]
Net cash provided by operating activities					18,669
Reporting Of Tax Remittances For Certain Equity Awards \| Overstatement
Subsidiary, Sale of Stock [Line Items]
Net cash provided by financing activities					18,669
Reporting Of Tax Remittances For Certain Equity Awards \| Revision of Prior Period, Error Correction, Adjustment
Subsidiary, Sale of Stock [Line Items]
Classification error, amount					$ 16,854
Additional Secondary Public Offering [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares) \| shares	16,383	12,000