Debt (Schedule of Maturities of Long-term Debt) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Long-term Debt, Fiscal Year Maturity [Abstract]
Long-Term Debt, Maturity, Remainder of Fiscal Year	$ 621
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	61,279
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	664,328
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Year Three	476,378
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	76,429
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	144,800
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	137,638
Long-term Debt, Gross	1,561,473
Debt Instrument, Unamortized Discount	(1,300)
Unamortized loan costs	(5,932)	$ (7,076)
Debt	$ 1,554,241	$ 1,440,465

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.

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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 requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing in remainder of current fiscal year.

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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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