CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Operating revenue	$ 225,063	$ 204,843	$ 550,619	$ 499,025
Production Expenses:
Purchased water	54,310	46,044	118,631	101,054
Power	3,396	2,785	8,560	7,363
Groundwater extraction charges	25,081	21,398	54,759	46,751
Other production expenses	12,919	12,415	36,020	36,379
Total production expenses	95,706	82,642	217,970	191,547
Administrative and general	25,708	23,888	71,964	71,759
Maintenance	8,512	6,457	23,080	18,813
Property taxes and other non-income taxes	9,361	8,795	26,610	25,092
Depreciation and amortization	27,423	26,455	84,159	78,872
Total operating expense	166,710	148,237	423,783	386,083
Operating income	58,353	56,606	126,836	112,942
Other (expense) income:
Interest on long-term debt and other interest expense	(17,516)	(16,744)	(53,394)	(48,913)
Pension non-service credit (cost)	940	(740)	2,829	(906)
Other, net	(1,197)	1,661	2,659	7,042
Income before income taxes	40,580	40,783	78,930	70,165
Provision for income taxes	1,928	4,561	7,883	4,127
Net income	38,652	36,222	71,047	66,038
Other comprehensive income (loss), net	0	318	(442)	420
Comprehensive income	$ 38,652	$ 36,540	$ 70,605	$ 66,458
Earnings per share
Basic (in usd per share)	$ 1.17	$ 1.14	$ 2.19	$ 2.10
Diluted (in usd per share)	1.17	1.13	2.18	2.09
Dividends per share (in usd per share)	$ 0.40	$ 0.38	$ 1.20	$ 1.14
Weighted average shares outstanding
Basic (in shares)	32,896,967	31,862,518	32,458,666	31,436,077
Diluted (in shares)	32,982,580	31,934,636	32,530,954	31,526,732