Fair Values of Assets and Liabilities - Quantitative Inputs and Assumptions Used in Level 3 Fair Value Measurements (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Investments	$ 25,397	$ 50,871
Assets	1,158,537	1,161,482
Limited Partnership Investment [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets	28,445	27,137
Level 3 [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Investments	6,182	6,182
Assets	$ 34,627	$ 33,319