Contracts in Progress and Advance Billings on Contracts - Components of Contracts in Progress and Advance Billings on Contracts (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Contractors [Abstract]
Costs incurred less costs of revenue recognized	$ 106,242	$ 90,191
Revenues recognized less billings to customers	409,176	267,426
Contracts in Progress	515,418	357,617
Billings to customers less revenue recognized	193,448	578,896
Costs incurred less costs of revenue recognized	(96,077)	(379,031)
Advance Billings on Contracts	$ 97,371	$ 199,865