Receivables and allowance for expected credit losses (Details 2) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Provision for credit losses							$ 9,769	$ 3,554
Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance	$ 6,873	$ 6,351	$ 4,154	$ 4,535	$ 5,030	$ 4,310	4,154	4,310
Provision for credit losses	3,907	2,097	3,765	1,070	497	1,988
Less write-offs charged against the allowance	3,357	1,873	1,943	2,373	1,277	1,600
Credit loss recoveries collected	308	298	375	294	285	332
Balance	7,731	6,873	6,351	3,526	4,535	5,030	7,731	3,526
Electric | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance	413	468	375	348	361	269	375	269
Provision for credit losses	513	182	615	300	113	565
Less write-offs charged against the allowance	572	316	667	399	234	597
Credit loss recoveries collected	75	79	145	85	108	124
Balance	429	413	468	334	348	361	429	334
Natural gas distribution | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance	1,740	2,943	1,615	1,453	2,123	1,506	1,615	1,506
Provision for credit losses	1,661	90	2,324	881	92	1,369
Less write-offs charged against the allowance	2,758	1,454	1,225	1,822	939	932
Credit loss recoveries collected	233	161	229	169	177	180
Balance	876	1,740	2,943	681	1,453	2,123	876	681
Pipeline | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance	2	2	2	2	2	2	2	2
Provision for credit losses	0	0	0	0	0	0
Less write-offs charged against the allowance	0	0	0	0	0	0
Credit loss recoveries collected	0	0	0	0	0	0
Balance	2	2	2	2	2	2	2	2
Construction services | Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance	4,718	2,938	2,162	2,732	2,544	2,533	2,162	2,533
Provision for credit losses	1,733	1,825	826	(111)	292	54
Less write-offs charged against the allowance	27	103	51	152	104	71
Credit loss recoveries collected	0	58	1	40	0	28
Balance	$ 6,424	$ 4,718	$ 2,938	$ 2,509	$ 2,732	$ 2,544	$ 6,424	$ 2,509