Debt and Credit Facilities (Tables)

3 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

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

The following table summarizes the maturities of our borrowing obligations as of December 31, 2017 (dollars in thousands):

Fiscal Year	Convertible Debentures(1)			Senior Notes			Total
2018	$	—		$	—		$	—
2019	—			—			—
2020	—			450,000			450,000
2021	—			—			—
2022	310,463			—			310,463
Thereafter	1,026,488			800,000			1,826,488
Total before unamortized discount	1,336,951			1,250,000			2,586,951
Less: unamortized discount and issuance costs	(277,455		)	(9,902		)	(287,357		)
Total long-term debt	$	1,059,496		$	1,240,098		$	2,299,594

⁽¹⁾  Pursuant to the terms of each convertible instrument, holders have the right to redeem the debt on specific dates prior to maturity. The repayment schedule above assumes that payment is due on the next redemption date after December 31, 2017.

Borrowing Obligations and Applicable Margin for Borrowings

At December 31, 2017 and September 30, 2017, we had the following long-term borrowing obligations (dollars in thousands):

	December 31, 2017			September 30, 2017
5.625% Senior Notes due 2026, net of deferred issuance costs of $5.5 million and $5.7 million, respectively. Effective interest rate 5.625%.	$	494,453		$	494,298
5.375% Senior Notes due 2020, net of unamortized premium of $0.9 million and $1.0 million, respectively, and deferred issuance costs of $2.1 million and $2.3 million, respectively. Effective interest rate 5.375%.	448,748			448,630
6.000% Senior Notes due 2024, net of deferred issuance costs of $2.0 million and $2.1 million, respectively. Effective interest rate 6.000%.	297,988			297,910
1.00% Convertible Debentures due 2035, net of unamortized discount of $135.0 million and $140.9 million, respectively, and deferred issuance costs of $6.6 million and $6.9 million, respectively. Effective interest rate 5.622%.	534,885			528,690
2.75% Convertible Debentures due 2031, net of unamortized discount of $1.5 million and deferred issuance costs of $0.1 million as of September 30, 2017. Effective interest rate 7.432%.	46,568			376,121
1.25% Convertible Debentures due 2025, net of unamortized discount of $90.2 million and $92.7 million, respectively, and deferred issuance costs of $4.1 million and $4.3 million, respectively. Effective interest rate 5.578%.	255,703			253,054
1.50% Convertible Debentures due 2035, net of unamortized discount of $40.1 million and $42.5 million, respectively, and deferred issuance costs of $1.4 million and $1.5 million, respectively. Effective interest rate 5.394%.	222,340			219,875
Deferred issuance costs related to our Revolving Credit Facility	(1,091		)	(1,174		)
Total debt	2,299,594			2,617,404
Less: current portion	—			376,121
Total long-term debt	$	2,299,594		$	2,241,283