v3.26.1
Fair Value Measurements (Summarize Changes in Level 3 Assets) (Details) - Level 3 - USD ($)
$ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance $ 30,929 $ 28,892
Assets, earnings (72) 1,971
Assets, other comprehensive income (217) 334
Assets, purchases 0 6,160
Assets, (sales) 1 (6,429)
Assets. transfers out   1
Securities transferred into or out of level 3, net 0  
Assets, ending balance 30,641 30,929
Debt securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance 20,001 19,667
Assets, earnings 0 0
Assets, other comprehensive income (217) 334
Assets, purchases 0 0
Assets, (sales) 0 0
Assets. transfers out   0
Securities transferred into or out of level 3, net 0  
Assets, ending balance 19,784 20,001
Equity securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance 10,815 5,715
Assets, earnings (72) 226
Assets, other comprehensive income 0 0
Assets, purchases 0 6,160
Assets, (sales) 1 (1,286)
Assets. transfers out 0 0
Assets, ending balance 10,744 10,815
Common stock    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance 2,141 2,041
Assets, earnings (72) 226
Assets, other comprehensive income 0 0
Assets, purchases 0 0
Assets, (sales) 0 (126)
Assets. transfers out 0 0
Assets, ending balance 2,069 2,141
Preferred stocks    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance 8,674 3,674
Assets, earnings 0 0
Assets, other comprehensive income 0 0
Assets, purchases 0 6,160
Assets, (sales) 1 (1,160)
Assets. transfers out 0 0
Assets, ending balance 8,675 8,674
Arbitrage trading account    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance 113 3,510
Assets, earnings 0 1,745
Assets, other comprehensive income 0 0
Assets, purchases 0 0
Assets, (sales) 0 (5,143)
Assets. transfers out   1
Securities transferred into or out of level 3, net 0  
Assets, ending balance 113 113
Corporate    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Assets, beginning balance 20,001 19,667
Assets, earnings 0 0
Assets, other comprehensive income (217) 334
Assets, purchases 0 0
Assets, (sales) 0 0
Securities transferred into or out of level 3, net 0 0
Assets, ending balance $ 19,784 $ 20,001