Contracts Receivable and Retainage - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified			6 Months Ended
Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Top Four Customer [Member] Customer
Long-term Contracts or Programs Disclosure [Line Items]
Contract receivable	$ 73,196	$ 60,535	$ 57,700
Number of major customers account for 78.8% of contract receivable			4
Percentage of contract receivable			78.80%

Amount billed to customers under long-term contracts or programs to be collected in the next fiscal year following the latest fiscal year. Excludes amounts due that have been withheld because of retainage provisions in a contract.

No definition available.

Name:	us-gaap_ContractReceivableDueOneYearOrLess
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant