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Earnings per Share - Schedule of Antidilutive securities (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss) available to common shareholders									$ 1,609	$ (13,118)	$ (37,932)
Weighted average basic shares outstanding (in shares)									29,812	25,438	25,115
Dilutive effect related to employee stock plans (in shares)									301	0	0
Weighted average diluted shares outstanding (in shares)									30,113	25,438	25,115
Diluted income (loss) per common share (in dollars per share)	$ 0.09	$ (0.45)	$ 0.18	$ 0.07	$ 0.09	$ (0.07)	$ (0.26)	$ (0.36)	$ 0.05	$ (0.52)	$ (1.51)
Anti-dilutive shares excluded (in shares)									21,035	21,754	21,355
Dilutive shares under the as-converted method (in shares)									51,134	46,971	46,382
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded (in shares)									14	733	334
Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded (in shares)									21,021	21,021	21,021