Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Revenue from reportable segments	$ 592,118	$ 535,176	$ 907,664	$ 798,765
Elimination of intersegment revenue	(52,503)	(50,502)	(57,889)	(57,360)
Revenue from external customers	539,615	484,674	849,775	741,405
Gross profit (loss)	51,916	44,956	76,852	74,944
Depreciation, Depletion and Amortization, Nonproduction	11,321	12,144	23,547	24,186
Assets	1,507,647	1,551,947	1,507,647	1,551,947	1,547,799
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit (loss)	51,916	44,956	76,852	74,944
Selling, general and administrative expenses	40,806	38,793	83,994	82,165
Gain on sales of property and equipment	2,954	3,270	4,871	5,974
Other income (expense), net	(7,718)	(1,173)	(3,602)	(2,972)
Income (loss) before provision for (benefit from) income taxes	6,346	8,260	(5,873)	(4,219)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Assets	652,828	687,771	652,828	687,771
Construction [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	245,113	260,600	363,059	353,292
Elimination of intersegment revenue	0	0	0	0
Revenue from external customers	245,113	260,600	363,059	353,292
Gross profit (loss)	17,961	23,389	26,541	28,942
Depreciation, Depletion and Amortization, Nonproduction	3,233	3,847	6,813	7,925
Assets	110,119	113,922	110,119	113,922
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit (loss)	17,961	23,389	26,541	28,942
Large Project Construction [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	228,799	162,338	392,727	300,158
Elimination of intersegment revenue	0	0	0	0
Revenue from external customers	228,799	162,338	392,727	300,158
Gross profit (loss)	28,239	12,658	50,488	43,956
Depreciation, Depletion and Amortization, Nonproduction	909	1,289	2,177	2,057
Assets	119,652	102,641	119,652	102,641
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit (loss)	28,239	12,658	50,488	43,956
Construction Materials [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	115,852	108,616	146,861	139,272
Elimination of intersegment revenue	(52,503)	(50,502)	(57,889)	(57,360)
Revenue from external customers	63,349	58,114	88,972	81,912
Gross profit (loss)	5,000	8,470	(950)	1,200
Depreciation, Depletion and Amortization, Nonproduction	7,179	7,000	14,557	14,107
Assets	365,690	382,892	365,690	382,892
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit (loss)	5,000	8,470	(950)	1,200
Real Estate Segment [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	2,354	3,622	5,017	6,043
Elimination of intersegment revenue	0	0	0	0
Revenue from external customers	2,354	3,622	5,017	6,043
Gross profit (loss)	716	439	773	846
Depreciation, Depletion and Amortization, Nonproduction	0	8	0	97
Assets	57,367	88,316	57,367	88,316
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit (loss)	$ 716	$ 439	$ 773	$ 846