Description of the Company and Basis of Presentation (Details) $ / shares in Units, shares in Thousands, $ in Thousands									3 Months Ended	12 Months Ended
	Aug. 10, 2020 shares	Mar. 10, 2020 shares	Oct. 29, 2018 segment	Mar. 21, 2018 shares	Mar. 19, 2018 shares	Nov. 07, 2017 shares	Nov. 06, 2017 USD ($) $ / shares shares	Jan. 16, 2014 USD ($)	Sep. 30, 2020 segment $ / shares	Sep. 30, 2020 segment $ / shares	Sep. 30, 2019 $ / shares
Subsidiary, Sale of Stock [Line Items]
Common stock, par value (in USD per share) | $ / shares									$ 0.01	$ 0.01	$ 0.01
Repayments of debt | $							$ 104,936
Number of reportable segments | segment			3						2	2
IPO [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction							27,777
Common stock, par value (in USD per share) | $ / shares							$ 0.01
Proceeds from issuance of common stock | $							$ 137,605
Initial Public Offering - Shares from Existing Shareholders [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction				2,625	17,500		8,333
Initial Public Offering - Shares from The Company [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction							19,444
Over-Allotment Option [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction						4,167
Additional Secondary Public Offering [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction	9,200	13,000
EWT Holdings II Corp and EWT Holdings III Corp [Member]
Subsidiary, Sale of Stock [Line Items]
Stock purchase price, net of cash received | $								$ 730,577