Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended			6 Months Ended	0 Months Ended
	Jun. 30, 2014 MW Country	Jun. 30, 2013	Jun. 30, 2014 Segment Supplier Location MW Country	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Department of Energy [Member]	Jun. 30, 2013 Department of Energy [Member]	Jun. 30, 2014 Power Generation [Member] Country	Jun. 30, 2014 Minimum [Member] Component	Apr. 14, 2014 Maximum [Member]	Jun. 30, 2014 Restricted Foreign Cash [Member]	Jun. 30, 2014 Cash Held for Future Decommissioning of Facilities [Member]	Jun. 30, 2014 Cash Held to Meet Reinsurance Reserve Requirements [Member]
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of business segments			5
Number of countries in which Company operates	30		30
Supplied electric generating capacity	300,000		300,000
Number of countries in which Company operates								80
Number of N-Stamp certified locations			2
Number of large, heavy-walled nuclear components and vessels suppliers			2
Number of large, heavy components supplied to worldwide									1,300
Operating period of light water nuclear technology			4 years
Investment for development										$ 15,000,000
Revenue recognition, percentage of contract completion			70.00%
Contract losses	4,000,000		11,600,000
Restricted cash and cash equivalents, net	42,300,000		42,300,000
Restricted cash and cash equivalents	39,660,000		39,660,000		45,945,000						3,300,000	2,600,000	36,400,000
Research and development activities	1,600,000	4,400,000	5,830,000	7,369,000
Funding award						150,000,000
Cost reimbursement percentage						50.00%
Authorized funding award						105,500,000
Additional allocation received						79,000,000
Recognized funding award						19,800,000	37,800,000
Effective tax rate	32.80%	29.80%	27.70%	28.60%
Gross unrecognized tax benefits	$ 5,900,000		$ 5,900,000