Senior Long-Term Debt and Other Debt (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Thousands	May 13, 2024	Sep. 30, 2024	Dec. 31, 2023	May 27, 2020
Series A preferred stock [Member]
Debt Instrument [Line Items]
Preferred stock, shares issued		600,000	600,000
Preferred stock, shares outstanding		600,000	600,000
Preferred stock, liquidation preference per share				$ 1,000
6.00% Unsecured Senior Note Due May 2054
Debt Instrument [Line Items]
Debt face amount	$ 600,000
Debt interest rate	6.00%
Proceeds from debt, net of issuance costs	$ 592,600