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
Segment Information [Abstract]
Number of reportable segments			4
Segment Reporting Information [Line Items]
Net sales to external customers	$ 253,875	$ 247,756	$ 520,513	$ 477,945
Intersegment sales	19,736	13,926	38,401	30,744
Gross profit	56,230	61,971	116,877	116,674
Gross profit (in hundredths)	22.10%	25.00%	22.50%	24.40%
Segment profit (loss)	11,316	13,968	23,047	25,373
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	11,316	13,968	23,047	25,373
Net income attributable to non-controlling interest in subsidiary	(63)	(19)	(76)	(33)
Recapture (elimination) of intersegment profit	(887)	137	(360)	(1,110)
Net income attributable to controlling interest	10,366	14,086	22,611	24,230
Asphalt Group [Member]
Segment Reporting Information [Line Items]
Number of business units			3
Net sales to external customers	59,431	68,183	128,101	141,937
Intersegment sales	6,140	5,897	14,050	10,355
Gross profit	11,775	16,750	28,171	35,978
Gross profit (in hundredths)	19.80%	24.60%	22.00%	25.30%
Segment profit (loss)	3,902	9,102	11,293	19,921
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	3,902	9,102	11,293	19,921
Aggregate and Mining Group [Member]
Segment Reporting Information [Line Items]
Number of business units			6
Net sales to external customers	94,860	86,562	186,164	165,415
Intersegment sales	6,320	4,980	13,316	12,144
Gross profit	25,818	22,406	49,555	41,155
Gross profit (in hundredths)	27.20%	25.90%	26.60%	24.90%
Segment profit (loss)	11,567	9,727	21,138	15,349
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	11,567	9,727	21,138	15,349
Mobile Asphalt Paving Group [Member]
Segment Reporting Information [Line Items]
Number of business units			3
Net sales to external customers	45,160	53,466	87,153	103,421
Intersegment sales	6,265	2,788	9,482	6,565
Gross profit	10,151	15,627	20,756	29,067
Gross profit (in hundredths)	22.50%	29.20%	23.80%	28.10%
Segment profit (loss)	4,082	8,532	8,003	15,843
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	4,082	8,532	8,003	15,843
Underground Group [Member]
Segment Reporting Information [Line Items]
Number of business units			3
Net sales to external customers	34,830	23,088	71,559	34,755
Intersegment sales	899	261	1,440	1,680
Gross profit	5,223	3,934	10,357	4,057
Gross profit (in hundredths)	15.00%	17.00%	14.50%	11.70%
Segment profit (loss)	355	172	483	(3,677)
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	355	172	483	(3,677)
All Others [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	19,594	16,457	47,536	32,417
Intersegment sales	112	0	113	0
Gross profit	3,263	3,254	8,038	6,417
Gross profit (in hundredths)	16.70%	19.80%	16.90%	19.80%
Segment profit (loss)	(8,590)	(13,565)	(17,870)	(22,063)
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	$ (8,590)	$ (13,565)	$ (17,870)	$ (22,063)