Segment Reporting - Schedule of Revenue Information by Products and Service Lines (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Revenues from External Customers [Line Items]
Revenues	$ 952,972	$ 866,286	$ 2,714,814	$ 2,312,583
Operating Segments
Revenues from External Customers [Line Items]
Revenues	953,278	867,668	2,718,626	2,316,363
Operating Segments \| Government Operations
Revenues from External Customers [Line Items]
Revenues	639,076	616,697	1,818,266	1,760,943
Operating Segments \| Commercial Operations
Revenues from External Customers [Line Items]
Revenues	314,202	250,971	900,360	555,420
Operating Segments \| Nuclear Components and Fuel \| Government Operations
Revenues from External Customers [Line Items]
Revenues	476,652	490,346	1,397,520	1,359,978
Operating Segments \| Uranium Processing and Nuclear Services \| Government Operations
Revenues from External Customers [Line Items]
Revenues	107,916	97,952	313,662	302,807
Operating Segments \| Advanced Reactor Design and Engineering \| Government Operations
Revenues from External Customers [Line Items]
Revenues	54,508	28,399	107,084	98,158
Operating Segments \| Nuclear Manufacturing \| Commercial Operations
Revenues from External Customers [Line Items]
Revenues	151,041	103,426	400,362	294,411
Operating Segments \| Nuclear Services and Engineering \| Commercial Operations
Revenues from External Customers [Line Items]
Revenues	163,161	147,545	499,998	261,009
Eliminations
Revenues from External Customers [Line Items]
Revenues	$ (306)	$ (1,382)	$ (3,812)	$ (3,780)