|
Contracts Receivable and Retainage - Additional Information (Detail) (USD $)
|
3 Months Ended | 12 Months Ended |
|---|---|---|
|
Mar. 31, 2013
|
Dec. 31, 2012
|
|
| Long-term Contracts or Programs Disclosure [Line Items] | ||
| Contract receivable | $ 134,191,000 | $ 60,535,000 |
| Costs and estimated earnings in excess of billings on uncompleted contracts | 24,867,000 | 26,317,000 |
|
Top Four Customer
|
||
| Long-term Contracts or Programs Disclosure [Line Items] | ||
| Contract receivable | 102,600,000 | |
| Number of major customers account for 76.4% of contract receivable | 4 | |
|
Cheviot Project
|
||
| Long-term Contracts or Programs Disclosure [Line Items] | ||
| Contract receivable | 30,900,000 | |
| Contract receivables monthly payments | 200,000 | |
| Contract receivables monthly payments end date | Feb. 28, 2013 | |
| Provision for loss on contract receivable | 14,500,000 | |
| Costs and estimated earnings in excess of billings on uncompleted contracts | $ 2,900,000 |