XML 183 R170.htm IDEA: XBRL DOCUMENT v3.23.3
10-Q Employee benefit plans - Components of net periodic benefit cost (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2023
Jun. 30, 2022
Jun. 30, 2023
Jun. 30, 2022
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Pension benefits              
Defined benefit plan disclosure, net periodic benefit cost [Line Items]              
Service cost         $ 0 $ 0  
Interest cost         1,127 1,053  
Other postretirement benefits              
Defined benefit plan disclosure, net periodic benefit cost [Line Items]              
Service cost         522 567  
Interest cost         514 492  
Qualified plan | Underfunded plan | Pension benefits              
Defined benefit plan disclosure, net periodic benefit cost [Line Items]              
Service cost         0 0 $ 0
Interest cost $ 408 $ 282 $ 816 $ 564 1,127 1,053 1,291
Expected return on assets (450) (493) (900) (986) (1,973) (2,028) (2,065)
Amortization of prior service credit         0 0 0
Amortization of net actuarial (gain) loss 128 214 256 428 856 971 862
Net periodic benefit cost 86 3 172 6 10 (4) 88
Qualified plan | Underfunded plan | Other postretirement benefits              
Defined benefit plan disclosure, net periodic benefit cost [Line Items]              
Service cost         522 567 554
Interest cost         514 492 650
Expected return on assets         (12) (19) (17)
Amortization of prior service credit         (79) (79) (79)
Amortization of net actuarial (gain) loss         351 135 306
Net periodic benefit cost         $ 1,296 $ 1,096 $ 1,414
Qualified plan | Unfunded plan | Other postretirement benefits              
Defined benefit plan disclosure, net periodic benefit cost [Line Items]              
Service cost 90 131 179 262      
Interest cost 180 128 361 256      
Expected return on assets 5 (3) 12 (6)      
Amortization of prior service credit (20) (20) (40) (40)      
Amortization of net actuarial (gain) loss (44) 88 (89) 176      
Net periodic benefit cost $ 211 $ 324 $ 423 $ 648