Debt - Debt (Parenthetical) (Detail) - USD ($)	Mar. 31, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 362,000	$ 404,000
Unsecured private placement 3.95% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	88,000	99,000
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	1,000	15,000
Unsecured private placement 2.30% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	72,000	77,000
Unsecured private placement 2.37% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	77,000	83,000
Unsecured private placement 2.73% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	66,000	70,000
Unsecured private placement 2.83% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 58,000	$ 60,000