Receivables, Net (Details) (USD $)	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	$ 360,421,000	$ 247,283,000	$ 379,245,000
Allowance for Accounts, Notes, Loans and Financing Receivable, Current	2,614,000	3,297,000	3,331,000
Receivables, net	357,807,000	243,986,000	375,914,000
Notes, Loans and Financing Receivable, Net, Noncurrent	2,100,000	1,800,000	2,100,000
Federal [Member] | Non Escrow [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	2,148,000	3,080,000	2,175,000
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-escrow retention receivable - current	1,976,000	2,587,000	1,921,000
Non-escrow retention receivable - 0 to 90 days past due	77,000	174,000	22,000
Non-escrow retention receivable - over 90 days past due	95,000	319,000	232,000
State [Member] | Non Escrow [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	6,046,000	9,507,000	10,792,000
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-escrow retention receivable - current	3,880,000	4,443,000	9,227,000
Non-escrow retention receivable - 0 to 90 days past due	1,397,000	628,000	131,000
Non-escrow retention receivable - over 90 days past due	769,000	4,436,000	1,434,000
Local [Member] | Non Escrow [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	17,666,000	29,451,000	30,409,000
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-escrow retention receivable - current	13,801,000	22,641,000	23,850,000
Non-escrow retention receivable - 0 to 90 days past due	1,465,000	2,800,000	2,489,000
Non-escrow retention receivable - over 90 days past due	2,400,000	4,010,000	4,070,000
Private [Member] | Non Escrow [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	10,418,000	10,454,000	10,926,000
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-escrow retention receivable - current	9,911,000	9,243,000	9,689,000
Non-escrow retention receivable - 0 to 90 days past due	108,000	175,000	243,000
Non-escrow retention receivable - over 90 days past due	399,000	1,036,000	994,000
Construction Contracts [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	298,087,000	217,997,000	318,806,000
Completed and in Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	223,292,000	121,664,000	226,192,000
Retentions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	74,795,000	96,333,000	92,614,000
Escrow [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	38,517,000	43,841,000	38,312,000
Non Escrow [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	36,278,000	52,492,000	54,302,000
Financing Receivable, Recorded Investment, Aging [Abstract]
Non-escrow retention receivable - current	29,568,000	38,914,000	44,687,000
Non-escrow retention receivable - 0 to 90 days past due	3,047,000	3,777,000	2,885,000
Non-escrow retention receivable - over 90 days past due	3,663,000	9,801,000	6,730,000
Construction Material Sales [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	52,157,000	17,674,000	51,114,000
Other Business Products and Services [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable, Gross, Current	$ 10,177,000	$ 11,612,000	$ 9,325,000