v3.26.1
Shareholders' Equity Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Balance, beginning of period $ 5,975,066 $ 5,774,378 $ 5,920,680 $ 5,550,957
Net change in unrealized gain (loss) (44,125) 86,829 (128,537) 260,657
Interest revenue, Investment securities 7,369 9,194 14,745 18,638
Loss on available-for-sale securities, net (4,645) 0 (4,645) 0
Other comprehensive income, before income taxes (32,111) 96,023 (109,147) 279,295
Federal and state income taxes (7,588) 22,690 (25,792) 65,265
Other comprehensive income, net of income taxes (24,523) 73,333 (83,355) 214,030
Balance, end of period 6,084,898 5,893,356 6,084,898 5,893,356
Accumulated Net Unrealized Gain (Loss) on Available for Sale Securities [Member]        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Balance, beginning of period     (102,569) (412,348)
Net change in unrealized gain (loss)     (128,537) 260,657
Interest revenue, Investment securities     0 0
Loss on available-for-sale securities, net     (4,645)  
Other comprehensive income, before income taxes     (123,892) 260,657
Federal and state income taxes     (29,277) 60,994
Other comprehensive income, net of income taxes     (94,615) 199,663
Balance, end of period (197,184) (212,685) (197,184) (212,685)
AOCI, Accumulated Gain (Loss), Debt Securities, Investment Securities Transferred from Available-for-sale, Parent        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Balance, beginning of period     (63,601) (90,692)
Net change in unrealized gain (loss)     0 0
Interest revenue, Investment securities     14,745 18,638
Loss on available-for-sale securities, net     0  
Other comprehensive income, before income taxes     14,745 18,638
Federal and state income taxes     3,485 4,271
Other comprehensive income, net of income taxes     11,260 14,367
Balance, end of period (52,341) (76,325) (52,341) (76,325)
Accumulated Other Comprehensive Income (Loss) [Member]        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Balance, beginning of period (225,002) (362,343) (166,170) (503,040)
Net change in unrealized gain (loss)     (128,537) 260,657
Interest revenue, Investment securities     14,745 18,638
Loss on available-for-sale securities, net     (4,645)  
Other comprehensive income, before income taxes     (109,147) 279,295
Federal and state income taxes     (25,792) 65,265
Other comprehensive income, net of income taxes (24,523) 73,333 (83,355) 214,030
Balance, end of period $ (249,525) $ (289,010) $ (249,525) $ (289,010)