Dividend Limitations (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Dividend limitations
Common shareholder’s equity	$ 1,045,581	$ 920,051	$ 776,109	$ 709,549
GSWC
Dividend limitations
Ratio of indebtedness to net capital	0.4352
Dividends paid	$ 37,500	35,100	55,400
Common shareholder’s equity	$ 933,737	$ 805,833	$ 703,828	$ 643,906
GSWC | Maximum
Dividend limitations
Ratio of indebtedness to net capital	0.6667