DERIVATIVE INSTRUMENTS - EFFECT OF DERIVATIVE INSTRUMENTS DESIGNATED AS CASH FLOW HEDGES ON OCI (Details) - Treasury Lock - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Derivative [Line Items]
Amount of Pre-tax Gain (Loss) Recognized in OCI on Derivatives	$ 0	$ (12,492)	$ 0	$ (12,492)
Interest expense
Derivative [Line Items]
Amount of Pre-tax Gain (Loss) Reclassified from OCI into Income	$ (342)	$ 0	$ (685)	$ 0