Contracts in Progress and Advance Billings on Contracts - Components of Contracts in Progress and Advance Billings on Contracts (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Contractors [Abstract]
Costs incurred less costs of revenue recognized	$ 107,199	$ 90,191
Revenues recognized less billings to customers	293,521	267,426
Contracts in Progress	400,720	357,617
Billings to customers less revenue recognized	324,128	578,896
Costs incurred less costs of revenue recognized	(211,042)	(379,031)
Advance Billings on Contracts	$ 113,086	$ 199,865