Debt Debt (Schedule of Maturities of Long-term Debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Maturities of Long-term Debt [Abstract]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	$ 1,219
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	121,267
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Year Three	501,315
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	426,366
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	51,416
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	357,801
Long-term Debt, Gross	1,459,384
Debt Instrument, Unamortized Discount	(2,065)
Unamortized loan costs	(7,959)	$ (9,884)
Debt, Long-term and Short-term, Combined Amount	$ 1,449,360	$ 1,281,675

Schedule of Maturities of Long-term Debt

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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Amount, after accumulated amortization, of debt discount.

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Represents the aggregate of total long-term debt, including current maturities and short-term debt.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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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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