Debt Instrument, Ratio of Principal to Public Offering Price

No definition available.

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- Definition

Gain (Loss) on Early Extinguishment of Debt

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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- Definition

Amount, after accumulated amortization, of debt discount.

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Gross amount of debt extinguished.

+ References

No definition available.

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- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The cash inflow from amounts received from issuance of long-term debt that is wholly or partially secured by collateral. Excludes proceeds from tax exempt secured debt.

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Schedule I - Condensed Financial Information Of Registrant (Long-Term Indebtedness) (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2017	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Unamortized discount - net			$ (6,900)	$ (6,800)
Debt Issuance Costs, Net			(24,400)	(22,200)
Long-term debt			2,477,538	2,499,490
Current portion of long-term debt			0	24,650
Net Long-term Debt			2,477,538	2,474,840
Ratio of principal to public offering price	99.901%
Charges related to early extinguishment of debt			8,875	0	$ 21,956
Gain (Loss) on Early Extinguishment of Debt			(8,875)	0	(21,956)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Unamortized discount - net			(534)	(273)
Debt Issuance Costs, Net			(7,863)	(5,018)
Long-term debt			801,603	799,709
Current portion of long-term debt			0	0
Net Long-term Debt			801,603	799,709
Refunded aggregate principal	$ 400,000
Charges related to early extinguishment of debt			$ 8,875	0	$ 21,956
Gain (Loss) on Early Extinguishment of Debt	$ 8,900
Parent Company [Member] \| 7.25% Senior Secured Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt		$ 33,500
Debt, stated interest rate			7.25%
Refunded aggregate principal		$ 366,500
Parent Company [Member] \| 5.00% Senior Secured Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt			$ 0	400,000
Debt, stated interest rate			5.00%
Debt due date			May 01, 2018
Parent Company [Member] \| 3.45% Senior Secured Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Long-term debt			$ 405,000	405,000
Debt, stated interest rate			3.45%
Debt due date			Jul. 01, 2020
Ratio of principal to public offering price		99.929%
Proceeds from Issuance of Secured Debt		$ 399,500
Parent Company [Member] \| Three Point Seven Zero Percent Senior Secured Notes [Domain]
Condensed Financial Statements, Captions [Line Items]
Long-term debt			$ 405,000	$ 0
Debt, stated interest rate			3.70%
Debt due date			Sep. 01, 2024
Proceeds from Issuance of Secured Debt			$ 399,300
First mortgage bonds			$ 405,000
Other Nonoperating Income (Expense) [Member] \| Parent Company [Member] \| 7.25% Senior Secured Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Charges related to early extinguishment of debt		$ 22,100