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OPUC (Details 4) - Tax Cuts and Jobs Act [Member] - OPUC [Member] - USD ($)	Jan. 22, 2019	May 31, 2018
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount		$ 2,300,000
Public utilities, requested rate increase (decrease), percentage		3.50%
Subsequent event [Member] | Natural gas rate proceeding [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount	$ 1,200,000
Public Utilities, Requested Rate Increase (Decrease) in Revenues Only, Amount	1,700,000
Public Utilities, Requested Rate Increase (Decrease) in Taxes Only, Amount	$ (500,000)

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