Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Revenue from reportable segments	$ 811,050	$ 815,981	$ 1,718,714	$ 1,614,746
Elimination of intersegment revenue	(82,568)	(87,403)	(140,457)	(144,763)
Revenue from external customers	728,482	728,578	1,578,257	1,469,983
Gross profit	101,099	93,893	177,951	168,837
Depreciation, Depletion and Amortization, Nonproduction	11,760	12,229	35,307	36,415
Assets	1,598,635	1,618,469	1,598,635	1,618,469	1,547,799
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit	101,099	93,893	177,951	168,837
Selling, general and administrative expenses	41,280	39,112	125,274	121,277
Gain on sales of property and equipment	1,622	5,598	6,493	11,572
Other income (expense), net	1,418	(2,894)	(2,184)	(5,866)
Income (loss) before provision for (benefit from) income taxes	62,859	57,485	56,986	53,266
Operating Segments [Member]
Segment Reporting Information [Line Items]
Assets	631,236	678,004	631,236	678,004
Construction [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	385,744	431,101	748,803	784,393
Elimination of intersegment revenue	0	0	0	0
Revenue from external customers	385,744	431,101	748,803	784,393
Gross profit	33,273	58,540	59,814	87,482
Depreciation, Depletion and Amortization, Nonproduction	3,160	3,437	9,973	11,362
Assets	110,402	114,359	110,402	114,359
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit	33,273	58,540	59,814	87,482
Large Project Construction [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	255,918	213,320	648,645	513,478
Elimination of intersegment revenue	0	0	0	0
Revenue from external customers	255,918	213,320	648,645	513,478
Gross profit	57,814	25,557	108,302	69,513
Depreciation, Depletion and Amortization, Nonproduction	1,102	1,259	3,279	3,316
Assets	109,114	108,272	109,114	108,272
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit	57,814	25,557	108,302	69,513
Construction Materials [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	169,350	170,574	316,211	309,846
Elimination of intersegment revenue	(82,568)	(87,403)	(140,457)	(144,763)
Revenue from external customers	86,782	83,171	175,754	165,083
Gross profit	9,984	9,554	9,034	10,754
Depreciation, Depletion and Amortization, Nonproduction	7,498	7,487	22,055	21,594
Assets	353,756	368,141	353,756	368,141
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit	9,984	9,554	9,034	10,754
Real Estate Segment [Member]
Segment Reporting Information [Line Items]
Revenue from reportable segments	38	986	5,055	7,029
Elimination of intersegment revenue	0	0	0	0
Revenue from external customers	38	986	5,055	7,029
Gross profit	28	242	801	1,088
Depreciation, Depletion and Amortization, Nonproduction	0	46	0	143
Assets	57,964	87,232	57,964	87,232
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit	$ 28	$ 242	$ 801	$ 1,088