v3.26.1
Consolidated Statements of Comprehensive Income - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Statement of Comprehensive Income [Abstract]        
Net income $ 21,240 $ 13,780 $ 102,057 $ 95,745
Postretirement liability adjustment:        
Amortization of postretirement liability losses included in net periodic benefit credit, net of tax of $50 and $33 for the three months ended and $85 and $51 for the six months ended in 2026 and 2025, respectively 159 103 333 221
Net unrealized (loss) gain on available-for-sale investments:        
Net unrealized (loss) gain on available-for-sale investments arising during the period, net of tax of $(10) and $4 for the three months ended and $(20) and $23 for the six months ended in 2026 and 2025, respectively (39) 14 (76) 85
Reclassification adjustment for loss on available-for-sale investments included in net income, net of tax of $1 and $1 for the three months ended and $2 and $1 for the six months ended in 2026 and 2025, respectively 3 3 6 6
Net unrealized (loss) gain on available-for-sale investments (36) 17 (70) 91
Other comprehensive income 123 120 263 312
Comprehensive income attributable to common stockholders $ 21,363 $ 13,900 $ 102,320 $ 96,057