Business Segment Information: Segment Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Segment Reporting, Asset Reconciling Item
Total Assets	$ 9,932,928	$ 9,618,230
Corporate and Other
Segment Reporting, Asset Reconciling Item
Total Assets	692,710	110,227
Electric Utilities | Operating Segments
Segment Reporting, Asset Reconciling Item
Total Assets	3,938,835	3,929,721
Gas Utilities | Operating Segments
Segment Reporting, Asset Reconciling Item
Total Assets	$ 5,301,383	$ 5,578,282