Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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-Publisher FASB
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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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DEBT - Summary of Interest Expense of Convertible Notes (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 19, 2020	Mar. 31, 2020	Sep. 30, 2019	Mar. 31, 2019
Debt Instrument [Line Items]
Amortization of debt discount and debt issuance costs		$ 5,387		$ 6,164
2.5% Convertible Notes debt 2021 \| Convertible debt
Debt Instrument [Line Items]
Stated coupon interest		607		2,156
Amortization of debt discount and debt issuance costs	$ 10,300	1,469	$ 26,100	4,807
Total interest expense Senior Notes		2,076		$ 6,963
5.0% Convertible Notes debt 2024 \| Convertible debt
Debt Instrument [Line Items]
Stated coupon interest		1,047
Amortization of debt discount and debt issuance costs	$ 38,100	1,219
Total interest expense Senior Notes		$ 2,266