Segment Reporting - Schedule of Revenue Information by Products and Service Lines (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Revenues from External Customers [Line Items]
Revenues	$ 901,625	$ 764,039	$ 1,761,842	$ 1,446,297
Operating Segments
Revenues from External Customers [Line Items]
Revenues	903,803	765,098	1,765,349	1,448,695
Operating Segments \| Government Operations
Revenues from External Customers [Line Items]
Revenues	601,291	588,959	1,179,191	1,144,246
Operating Segments \| Commercial Operations
Revenues from External Customers [Line Items]
Revenues	302,512	176,139	586,158	304,449
Operating Segments \| Nuclear Components and Fuel \| Government Operations
Revenues from External Customers [Line Items]
Revenues	472,463	428,552	920,867	869,631
Operating Segments \| Uranium Processing and Nuclear Services \| Government Operations
Revenues from External Customers [Line Items]
Revenues	104,467	121,690	205,747	204,855
Operating Segments \| Advanced Reactor Design and Engineering \| Government Operations
Revenues from External Customers [Line Items]
Revenues	24,361	38,717	52,577	69,760
Operating Segments \| Nuclear Manufacturing \| Commercial Operations
Revenues from External Customers [Line Items]
Revenues	129,115	104,775	249,321	190,985
Operating Segments \| Nuclear Services and Engineering \| Commercial Operations
Revenues from External Customers [Line Items]
Revenues	173,397	71,364	336,837	113,464
Eliminations
Revenues from External Customers [Line Items]
Revenues	$ (2,178)	$ (1,059)	$ (3,507)	$ (2,398)