Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment Reporting Information [Line Items]
Net sales to external customers	$ 247,756	$ 209,249	$ 477,945	$ 402,704
Intersegment sales	13,926	12,121	30,744	31,341
Gross profit	61,971	46,678	116,674	92,820
Gross profit percent (in hundredths)	25.00%	22.30%	24.40%	23.00%
Segment profit (loss)	13,968	10,841	25,373	20,617
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	13,968	10,841	25,373	20,617
Net income attributable to non-controlling interest in subsidiary	(19)	(22)	(33)	(60)
Recapture (elimination) of intersegment profit	137	(511)	(1,110)	(1,455)
Net income attributable to controlling interest	14,086	10,308	24,230	19,102
Asphalt Group Segment [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	68,183	65,362	141,937	135,423
Intersegment sales	5,897	3,558	10,355	10,111
Gross profit	16,750	14,961	35,978	35,168
Gross profit percent (in hundredths)	24.60%	22.90%	25.30%	26.00%
Segment profit (loss)	9,102	7,574	19,921	20,369
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	9,102	7,574	19,921	20,369
Aggregate and Mining Group Segment [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	86,562	67,000	165,415	125,919
Intersegment sales	4,980	4,555	12,144	12,149
Gross profit	22,406	15,199	41,155	28,386
Gross profit percent (in hundredths)	25.90%	22.70%	24.90%	22.50%
Segment profit (loss)	9,727	4,973	15,349	7,795
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	9,727	4,973	15,349	7,795
Mobile Asphalt Paving Group Segment [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	53,466	47,231	103,421	89,314
Intersegment sales	2,788	3,057	6,565	7,198
Gross profit	15,627	12,233	29,067	22,743
Gross profit percent (in hundredths)	29.20%	25.90%	28.10%	25.50%
Segment profit (loss)	8,532	6,264	15,843	11,475
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	8,532	6,264	15,843	11,475
Underground Group Segment [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	23,088	13,636	34,755	22,563
Intersegment sales	261	951	1,680	1,883
Gross profit	3,934	868	4,057	511
Gross profit percent (in hundredths)	17.00%	6.40%	11.70%	2.30%
Segment profit (loss)	172	(1,901)	(3,677)	(5,443)
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	172	(1,901)	(3,677)	(5,443)
All Others [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	16,457	16,020	32,417	29,485
Intersegment sales	0	0	0	0
Gross profit	3,254	3,417	6,417	6,012
Gross profit percent (in hundredths)	19.80%	21.30%	19.80%	20.40%
Segment profit (loss)	(13,565)	(6,069)	(22,063)	(13,579)
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	$ (13,565)	$ (6,069)	$ (22,063)	$ (13,579)