Contracts in Progress and Advance Billings on Contracts - Components of Contracts in Progress and Advance Billings on Contracts (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Contractors [Abstract]
Costs incurred less costs of revenue recognized	$ 108,043	$ 112,819
Revenues recognized less billings to customers	193,693	323,010
Contracts in Progress	301,736	435,829
Billings to customers less revenue recognized	20,532	265,618
Costs incurred less costs of revenue recognized	63,748	(100,845)
Advance Billings on Contracts	$ 84,280	$ 164,773