v3.26.1
Shareholders' Equity (Schedule of Components of AOCI, Net of Tax) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance $ 1,349,134 $ 1,201,749
OCI, before reclassifications, net of tax (19,617) 35,575
Amounts reclassified from AOCI, net of tax 1,681 1,958
Net OCI, current period (17,936) 37,533
Ending balance 1,338,770 1,233,620
Accumulated Other Comprehensive Income (Loss)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance (81,046) (172,391)
Ending balance (98,982) (134,858)
Unrealized Investment Gains (Losses)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance (81,392) (176,053)
OCI, before reclassifications, net of tax (20,921) 37,212
Amounts reclassified from AOCI, net of tax 1,905 2,425
Net OCI, current period (19,016) 39,637
Ending balance (100,408) (136,416)
Cash Flow Hedging Gains (Losses)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 312 4,576
OCI, before reclassifications, net of tax 1,304 (1,637)
Amounts reclassified from AOCI, net of tax (224) (548)
Net OCI, current period 1,080 (2,185)
Ending balance 1,392 2,391
Non-credit Impairments    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance (375) (92)
OCI, before reclassifications, net of tax 0 0
Amounts reclassified from AOCI, net of tax 0 81
Net OCI, current period 0 81
Ending balance (375) (11)
Unrecognized Change in Defined Benefit Plan Liabilities    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 409 (822)
OCI, before reclassifications, net of tax 0 0
Amounts reclassified from AOCI, net of tax 0 0
Net OCI, current period 0 0
Ending balance $ 409 $ (822)