Employee Benefit Plans - Fair Value Hierarchy (Details) - Post-Retirement Medical Benefits - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Employee benefit plans
Total investments measured at fair value	$ 16,019	$ 14,456	$ 12,827
Fair Value
Employee benefit plans
Total investments measured at fair value	16,019	14,456
Level 1
Employee benefit plans
Total investments measured at fair value	16,019	14,456
Level 2
Employee benefit plans
Total investments measured at fair value	0	0
Level 3
Employee benefit plans
Total investments measured at fair value	0	0
Cash equivalents | Fair Value
Employee benefit plans
Total investments measured at fair value	188	110
Cash equivalents | Level 1
Employee benefit plans
Total investments measured at fair value	188	110
Cash equivalents | Level 2
Employee benefit plans
Total investments measured at fair value	0	0
Cash equivalents | Level 3
Employee benefit plans
Total investments measured at fair value	0	0
Fixed income fund | Fair Value
Employee benefit plans
Total investments measured at fair value	6,339	5,818
Fixed income fund | Level 1
Employee benefit plans
Total investments measured at fair value	6,339	5,818
Fixed income fund | Level 2
Employee benefit plans
Total investments measured at fair value	0	0
Fixed income fund | Level 3
Employee benefit plans
Total investments measured at fair value	0	0
U.S. equity securities | Fair Value
Employee benefit plans
Total investments measured at fair value	9,492	8,528
U.S. equity securities | Level 1
Employee benefit plans
Total investments measured at fair value	9,492	8,528
U.S. equity securities | Level 2
Employee benefit plans
Total investments measured at fair value	0	0
U.S. equity securities | Level 3
Employee benefit plans
Total investments measured at fair value	$ 0	$ 0