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Description of the Company and Basis of Presentation (Details) $ / shares in Units, shares in Thousands, $ in Thousands							3 Months Ended
	Oct. 29, 2018 segment	Mar. 21, 2018 shares	Mar. 19, 2018 shares	Nov. 07, 2017 shares	Nov. 06, 2017 $ / shares shares	Jan. 16, 2014 USD ($)	Dec. 31, 2019 segment $ / shares	Dec. 31, 2017 USD ($)	Sep. 30, 2019 $ / shares
Subsidiary, Sale of Stock [Line Items]
Common stock, par value (in USD per share) \| $ / shares							$ 0.01		$ 0.01
Repayments of debt \| $								$ 104,936
Number of reportable segments \| segment	3						2
IPO
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)					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
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)		2,625	17,500		8,333
Initial Public Offering - Shares from The Company
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)					19,444
Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Number of shares issued in transaction (in shares)				4,167
EWT Holdings II Corp and EWT Holdings III Corp
Subsidiary, Sale of Stock [Line Items]
Stock purchase price, net of cash received \| $						$ 730,577