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v3.21.2

Investment in ATC and ATC Holdco (Details-2) - ATC [Member] - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Schedule Of Equity Method Investments [Line Items] |  |  |  |
Operating revenues | $ 186,785 | $ 187,833 | $ 561,379 | $ 577,705
Operating expenses | (91,340) | (92,975) | (278,828) | (285,697)
Other income, net | 123 | 643 | 1,164 | 1,924
Interest expense, net | (28,674) | (28,801) | (86,337) | (83,947)
Earnings before members' income taxes | $ 66,894 | $ 66,700 | $ 197,378 | $ 209,985

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