Income (Loss) Per Common Share - Additional Information (Details)	3 Months Ended	6 Months Ended
Mar. 31, 2018 shares	Mar. 31, 2019 shares	Mar. 31, 2018 shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Split of common stock ratio		2
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of stock excluded from calcuation of weighted average shares outstandiing	194,600	163,800	194,600
Non-Vested RSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Number of stock excluded from calcuation of weighted average shares outstandiing	0	161,300	0

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

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