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COMMON STOCK EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 12 Months Ended
--- | --- | ---
Dec. 04, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2018
Class of Stock [Line Items] |  |  |  |
Number of shares issued in transaction (in shares) | 6,545,454 |  |  |
Proceeds from issuance of common stock | $ 212,900 | $ 18,080 | $ 16,717 | $ 17,136
Forward sales agreement, settlement (in shares) |  | 543,150 |  |
Directly Issued Common Stock |  |  |  |
Class of Stock [Line Items] |  |  |  |
Number of shares issued in transaction (in shares) | 5,333,334 |  |  |
Forward Sales Agreements |  |  |  |
Class of Stock [Line Items] |  |  |  |
Number of shares issued in transaction (in shares) | 1,212,120 |  |  |
Conversion price per share (usd per share) | $ 40.0125 |  |  |
Forward sales agreement, settlement, amount |  | $ 14,300 |  |

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