v3.25.2
Accumulated Other Comprehensive Income (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Accumulated Other Comprehensive Income (Loss) before Tax [Roll Forward]        
Beginning Balance $ 4,186,763 $ 3,967,585 $ 4,234,666 $ 3,743,897
Total other comprehensive income (loss) (38,674) (11,347) (38,045) 90,213
Ending Balance 4,315,059 3,986,470 4,315,059 3,986,470
Unrealized Gains (Losses) on AFS Securities        
Accumulated Other Comprehensive Income (Loss) before Tax [Roll Forward]        
Beginning Balance 11,985 41,539 11,668 (59,777)
Net change in unrealized gains (losses) (39,710) (7,074) (36,689) 94,242
Net realized (gains) from sales of AFS securities   (1,840) (2,704) (1,840)
Pension benefits, net 0 0 0 0
Total other comprehensive income (loss) (39,710) (8,914) (39,393) 92,402
Ending Balance (27,725) 32,625 (27,725) 32,625
Pension Benefits        
Accumulated Other Comprehensive Income (Loss) before Tax [Roll Forward]        
Beginning Balance (16,196) (13,511) (16,508) (13,755)
Net change in unrealized gains (losses) 0 0 0 0
Net realized (gains) from sales of AFS securities   0 0 0
Pension benefits, net 1,036 (2,433) 1,348 (2,189)
Total other comprehensive income (loss) 1,036 (2,433) 1,348 (2,189)
Ending Balance (15,160) (15,944) (15,160) (15,944)
Accumulated Other Comprehensive Income (Loss)        
Accumulated Other Comprehensive Income (Loss) before Tax [Roll Forward]        
Beginning Balance (4,211) 28,028 (4,840) (73,532)
Net change in unrealized gains (losses) (39,710) (7,074) (36,689) 94,242
Net realized (gains) from sales of AFS securities   (1,840) (2,704) (1,840)
Pension benefits, net 1,036 (2,433) 1,348 (2,189)
Total other comprehensive income (loss) (38,674) (11,347) (38,045) 90,213
Ending Balance $ (42,885) $ 16,681 $ (42,885) $ 16,681