Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt discount (premium).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Borrowings - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Sep. 30, 2016	Jul. 30, 2016
Debt Instrument [Line Items]
Unamortized debt premium, net	$ (3,606)	$ (1,482)
Debt issuance costs	14,908	15,514
Total debt, net	1,334,623	1,331,878
Senior Notes
Debt Instrument [Line Items]
Unamortized debt premium, net	(3,606)	(2,362)
Debt issuance costs	15,575	14,063
Total debt, net	$ 1,259,258	$ 1,207,526
Senior Notes \| 5 3/4% Senior Notes Maturing June 2019
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	5.75%	5.75%
Total debt, net	$ 321,393	$ 321,393
Senior Notes \| 7 1/2% Senior Notes Maturing September 2021
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	7.50%	7.50%
Total debt, net	$ 0	$ 198,000
Senior Notes \| 8 3/4% Senior Notes Maturing March 2022
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	8.75%	8.75%
Total debt, net	$ 500,000	$ 500,000
Senior Notes \| 7 1/4% Senior Notes Maturing February 2023
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)	7.25%	7.25%
Total debt, net	$ 199,834	$ 199,834
Senior Notes \| 6 3/4% Senior Notes Maturing March 2025
Debt Instrument [Line Items]
Total debt, net	250,000	0
Term Loan
Debt Instrument [Line Items]
Total debt, net	0	52,669
Junior Subordinated Notes
Debt Instrument [Line Items]
Stated interest rate on debt instrument (percent)			7.987%
Total debt, net	61,420	59,870
Other Secured Notes payable
Debt Instrument [Line Items]
Total debt, net	$ 13,945	$ 11,813