Contracts in Progress and Advance Billings on Contracts - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Contractors [Abstract]
Contracts in progress	$ 380,756	$ 357,617
Advance billing on contracts	$ 162,004	$ 199,865

Amount of increase (decrease) in the asset reflecting the cost incurred on uncompleted contracts in excess of related billings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Name:	us-gaap_IncreaseDecreaseInCostInExcessOfBillingOnUncompletedContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration