Debt and Credit Facilities (Tables)

9 Months Ended

Jun. 30, 2020

Debt Disclosure [Abstract]

Schedule of Maturities of Long-term Debt [Table Text Block]

^(a) As of September 30, 2019, in connection with the anticipated Cerence spin-off, the holders had the right to convert all or any portion of their debentures until the close of business on October 1, 2019. As a result, the net carrying amounts of our convertible notes were included in current liabilities as of September 30, 2019. Upon the conclusion of

Borrowing Obligations and Applicable Margin for Borrowings

As of June 30, 2020 and September 30, 2019, we had the following borrowing obligations (dollars in thousands): 

	June 30, 2020			September 30, 2019
5.625% Senior Notes due 2026, net of deferred issuance costs of $4.0 million and $4.5 million, respectively. Effective interest rate 5.625%.	$	495,994		$	495,518
6.000% Senior Notes due 2024, net of deferred issuance costs of $1.5 million. Effective interest rate 6.000%.	—			298,529
1.000% Convertible Debentures due 2035, net of unamortized discount of $71.6 million and $91.6 million, respectively, and deferred issuance costs of $3.3 million and $4.3 million, respectively. Effective interest rate 5.622%.	601,593			580,639
2.750% Convertible Debentures due 2031. Effective interest rate 7.432%.	—			46,568
1.250% Convertible Debentures due 2025, net of unamortized discount of $47.3 million and $71.6 million, respectively, and deferred issuance costs of $2.0 million and $3.1 million, respectively. Effective interest rate 5.578%.	213,283			275,257
1.500% Convertible Debentures due 2035, net of unamortized discount of $12.8 million and $22.7 million, respectively, and deferred issuance costs of $0.4 million and $0.8 million, respectively. Effective interest rate 5.394%.	214,217			240,406
Deferred issuance costs related to our Revolving Credit Facility	(262		)	(511		)
Total debt	1,524,825			1,936,406
Less: current portion (a)	—			(1,142,870		)
Total long-term debt	$	1,524,825		$	793,536