Fair Value Measurement - Quantitative Information Regarding Level 3 Valuations (Details) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Assets:
Estimated Fair Value	$ 3,582,207	$ 3,493,597
Other investments	226,269	245,455
Fair Value, Inputs, Level 3
Assets:
Equity investments	5,506	5,237
Other investments	500	5,126
Liabilities:
Other liabilities	$ 0	6,500
Fair Value, Inputs, Level 3 | Discounted Cash Flows | Comparability Adjustment | Minimum
Assets:
Equity securities measured at fair value	0
Other investments, measurement input	0
Fair Value, Inputs, Level 3 | Discounted Cash Flows | Comparability Adjustment | Maximum
Assets:
Equity securities measured at fair value	0.10
Other investments, measurement input	0.10
Fair Value, Inputs, Level 3 | Discounted Cash Flows | Comparability Adjustment | Weighted Average
Assets:
Equity securities measured at fair value	0.05
Other investments, measurement input	0.05
Fair Value, Inputs, Level 3 | Stochastic Model/Discounted Cash Flows | Weighted Average Cost of Capital | Minimum
Liabilities:
Other liabilities, measurement input	0.00%
Fair Value, Inputs, Level 3 | Stochastic Model/Discounted Cash Flows | Weighted Average Cost of Capital | Maximum
Liabilities:
Other liabilities, measurement input	10.00%
Fair Value, Inputs, Level 3 | Stochastic Model/Discounted Cash Flows | Weighted Average Cost of Capital | Weighted Average
Liabilities:
Other liabilities, measurement input	8.00%
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs
Assets:
Estimated Fair Value	$ 81,062	82,377
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs | Market Comparable Securities | Comparability Adjustment | Minimum
Assets:
Assets measured at fair value	0
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs | Market Comparable Securities | Comparability Adjustment | Maximum
Assets:
Assets measured at fair value	0.05
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs | Market Comparable Securities | Comparability Adjustment | Weighted Average
Assets:
Assets measured at fair value	0.025
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs | Discounted Cash Flows | Comparability Adjustment | Minimum
Assets:
Assets measured at fair value	0
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs | Discounted Cash Flows | Comparability Adjustment | Maximum
Assets:
Assets measured at fair value	0.05
Fair Value, Inputs, Level 3 | Corporate debt, limited observable inputs | Discounted Cash Flows | Comparability Adjustment | Weighted Average
Assets:
Assets measured at fair value	0.025
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities
Assets:
Estimated Fair Value	$ 3,774	$ 4,414
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Market Comparable Securities | Comparability Adjustment | Minimum
Assets:
Assets measured at fair value	0
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Market Comparable Securities | Comparability Adjustment | Maximum
Assets:
Assets measured at fair value	0.05
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Market Comparable Securities | Comparability Adjustment | Weighted Average
Assets:
Assets measured at fair value	0.025
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Discounted Cash Flows | Comparability Adjustment | Minimum
Assets:
Assets measured at fair value	0
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Discounted Cash Flows | Comparability Adjustment | Maximum
Assets:
Assets measured at fair value	0.05
Fair Value, Inputs, Level 3 | Residential mortgage-backed, other commercial mortgage-backed and other asset-backed securities | Discounted Cash Flows | Comparability Adjustment | Weighted Average
Assets:
Assets measured at fair value	0.025