v3.26.1
Fair Value Measurement (Schedule of Quantitative Information Regarding Level 3 Valuations) (Details)
$ in Thousands
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
Assets:    
Estimated Fair Value $ 3,643,213 $ 3,685,787
Level 3 | Corporate debt, limited observable inputs    
Assets:    
Estimated Fair Value $ 83,883 79,511
Level 3 | Corporate debt, limited observable inputs | Market Comparable Securities | Comparability Adjustment | Minimum    
Assets:    
Assets measured at fair value 0  
Level 3 | Corporate debt, limited observable inputs | Market Comparable Securities | Comparability Adjustment | Maximum    
Assets:    
Assets measured at fair value 0.05  
Level 3 | Corporate debt, limited observable inputs | Market Comparable Securities | Comparability Adjustment | Weighted Average    
Assets:    
Assets measured at fair value 0.025  
Level 3 | Corporate debt, limited observable inputs | Discounted Cash Flows | Comparability Adjustment | Minimum    
Assets:    
Assets measured at fair value 0  
Level 3 | Corporate debt, limited observable inputs | Discounted Cash Flows | Comparability Adjustment | Maximum    
Assets:    
Assets measured at fair value 0.05  
Level 3 | Corporate debt, limited observable inputs | Discounted Cash Flows | Comparability Adjustment | Weighted Average    
Assets:    
Assets measured at fair value 0.025  
Level 3 | Other asset-backed securities    
Assets:    
Estimated Fair Value $ 5,346 $ 3,504
Level 3 | Other asset-backed securities | Market Comparable Securities | Comparability Adjustment | Minimum    
Assets:    
Assets measured at fair value 0  
Level 3 | Other asset-backed securities | Market Comparable Securities | Comparability Adjustment | Maximum    
Assets:    
Assets measured at fair value 0.05  
Level 3 | Other asset-backed securities | Market Comparable Securities | Comparability Adjustment | Weighted Average    
Assets:    
Assets measured at fair value 0.025  
Level 3 | Other asset-backed securities | Discounted Cash Flows | Comparability Adjustment | Minimum    
Assets:    
Assets measured at fair value 0  
Level 3 | Other asset-backed securities | Discounted Cash Flows | Comparability Adjustment | Maximum    
Assets:    
Assets measured at fair value 0.05  
Level 3 | Other asset-backed securities | Discounted Cash Flows | Comparability Adjustment | Weighted Average    
Assets:    
Assets measured at fair value 0.025