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Percentage of reserve on receivables overdue one to thirty days (in hundredths)

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- Definition

Percentage of reserve on receivables overdue one year (in hundredths)

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- Definition

Period for general reserve with specific minimum percentage.

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- Definition

Significant Accounting Policies [Line Items]

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

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Amount of lessee's right to use underlying asset under operating lease.

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The estimated or actual value of the asset at the end of its useful life or when it is no longer serviceable (cannot be used for its original purpose).

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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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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Summary Of Significant Accounting Policies And Recent Accounting Pronouncements (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Goodwill	$ 15,794,000	$ 15,794,000			$ 15,800,000	$ 15,800,000
Impairment charges	0	0	$ 0
Impairment of goodwill	$ 0
Percentage of general reserve on receivables one to thirty days overdue	1.00%
Percentage of reserve on receivables one year overdue	100.00%
Maximum period for general reserve with specific maximum percentage	1 year
Unamortized debt issuance cost	$ 14,800,000	$ 20,400,000
Operating Lease, Liability	$ 7,163,000
Accounting Standards Update 2016-02 [Member]
Significant Accounting Policies [Line Items]
Operating Lease, Right-of-Use Asset				$ 3,700,000
Operating Lease, Liability				$ 4,100,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Period for general reserve with specific minimum percentage	1 day
Minimum [Member] \| Other Specialized Equipment [Member]
Significant Accounting Policies [Line Items]
Estimated useful life	12 years 6 months
Residual value	$ 1,000
Maximum [Member]
Significant Accounting Policies [Line Items]
Period for general reserve with specific minimum percentage	30 days
Maximum [Member] \| Other Specialized Equipment [Member]
Significant Accounting Policies [Line Items]
Estimated useful life	15 years
Residual value	$ 3,500