Quarterly report [Sections 13 or 15(d)]

Changes in Equity - Changes in Equity (Details)

v3.26.1
Changes in Equity - Changes in Equity (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Beginning balance $ 1,555,946 $ 1,458,907 $ 1,206,257 $ 1,132,465 $ 1,458,907 $ 1,132,465
Net income 153,930 142,902 116,140 120,652 296,832 236,792
Regular dividends paid and accrued (41,387) (41,796) (36,782) (37,434)    
Share-based compensation, net of forfeitures 4,318 5,355 3,419 4,873    
Shares exchanged for tax withholdings (51) (9,063) (51) (14,260)    
Periodic pension costs, net of income taxes (358) (359) (39) (39) (717) (78)
Ending balance $ 1,672,398 $ 1,555,946 $ 1,288,944 $ 1,206,257 $ 1,672,398 $ 1,288,944
Dividends accrued per common stock (in dollars per share) $ 0.60 $ 0.60 $ 0.53 $ 0.53 $ 1.20 $ 1.06
Amortization of net actuarial costs and prior service costs, income taxes $ 96 $ 95 $ 10 $ 11 $ 191 $ 21
Common Stock            
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Beginning balance (in shares) 68,974,187 68,938,230 68,961,735 68,915,409 68,938,230 68,915,409
Beginning balance $ 691 $ 691 $ 231 $ 231 $ 691 $ 231
Share-based compensation, net of forfeitures (in shares) 611 57,967 357 77,670    
Shares exchanged for tax withholdings (in shares) (115) (22,010) (114) (31,344)    
Ending balance (in shares) 68,974,683 68,974,187 68,961,978 68,961,735 68,974,683 68,961,978
Ending balance $ 691 $ 691 $ 231 $ 231 $ 691 $ 231
Treasury Stock            
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Beginning balance (132,908) (151,242) (144,850) (168,843) (151,242) (168,843)
Share-based compensation, net of forfeitures 286 27,397 174 38,253    
Shares exchanged for tax withholdings (51) (9,063) (51) (14,260)    
Ending balance (132,673) (132,908) (144,727) (144,850) (132,673) (144,727)
Additional Paid-in Capital            
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Beginning balance 2,909 9,906 2,122 19,900 9,906 19,900
Share-based compensation, net of forfeitures 4,102 (6,997) 3,311 (17,778)    
Ending balance 7,011 2,909 5,433 2,122 7,011 5,433
Accum. Other Comp. Income (Loss)            
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Beginning balance 3,791 4,150 3,544 3,583 4,150 3,583
Periodic pension costs, net of income taxes (358) (359) (39) (39)    
Ending balance 3,433 3,791 3,505 3,544 3,433 3,505
Retained Earnings            
Increase (Decrease) in Stockholders' Equity [Roll Forward]            
Beginning balance 1,681,463 1,595,402 1,345,210 1,277,594 1,595,402 1,277,594
Net income 153,930 142,902 116,140 120,652    
Regular dividends paid and accrued (41,387) (41,796) (36,782) (37,434)    
Share-based compensation, net of forfeitures (70) (15,045) (66) (15,602)    
Ending balance $ 1,793,936 $ 1,681,463 $ 1,424,502 $ 1,345,210 $ 1,793,936 $ 1,424,502