Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Segment	Sep. 30, 2012
Segment Information [Abstract]
Number of reportable segments			4
Segment Reporting Information [Line Items]
Net sales to external customers	$ 213,177,000	$ 218,391,000	$ 709,136,000	$ 708,633,000
Gross profit	45,787,000	47,297,000	159,795,000	159,640,000
Gross profit (in hundredths)	21.50%	21.70%	22.50%	22.50%
Segment profit (loss)	7,205,000	7,282,000	32,358,000	29,676,000
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	7,205,000	7,282,000	32,358,000	29,676,000
Elimination of intersegment profit	(678,000)	(649,000)	(1,428,000)	(1,009,000)
Net income from continuing operations	6,527,000	6,633,000	30,930,000	28,667,000
Income from discontinued operations, net of tax	0	318,000	0	1,400,000
Net income attributable to non-controlling interest in subsidiary	(13,000)	(48,000)	(154,000)	(124,000)
Net income attributable to controlling interest	6,514,000	6,903,000	30,776,000	29,943,000
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	18,983,000	16,182,000	63,662,000	54,101,000
Asphalt Group [Member]
Segment Reporting Information [Line Items]
Number of business units			3
Net sales to external customers	47,058,000	46,797,000	181,761,000	174,898,000
Gross profit	12,257,000	9,645,000	44,289,000	38,502,000
Gross profit (in hundredths)	26.00%	20.60%	24.40%	22.00%
Segment profit (loss)	4,846,000	2,324,000	20,048,000	14,308,000
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	4,846,000	2,324,000	20,048,000	14,308,000
Asphalt Group [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	3,686,000	5,860,000	11,432,000	19,910,000
Aggregate and Mining Group [Member]
Segment Reporting Information [Line Items]
Number of business units			7
Net sales to external customers	79,792,000	91,860,000	270,438,000	278,024,000
Gross profit	19,584,000	22,957,000	68,240,000	72,512,000
Gross profit (in hundredths)	24.50%	25.00%	25.20%	26.10%
Segment profit (loss)	6,765,000	8,697,000	26,963,000	29,836,000
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	6,765,000	8,697,000	26,963,000	29,836,000
Aggregate and Mining Group [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	11,301,000	5,939,000	34,361,000	19,256,000
Mobile Asphalt Paving Group [Member]
Segment Reporting Information [Line Items]
Number of business units			3
Net sales to external customers	35,419,000	36,618,000	128,459,000	123,770,000
Gross profit	7,922,000	7,575,000	29,652,000	28,331,000
Gross profit (in hundredths)	22.40%	20.70%	23.10%	22.90%
Segment profit (loss)	2,059,000	1,631,000	10,888,000	9,634,000
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	2,059,000	1,631,000	10,888,000	9,634,000
Mobile Asphalt Paving Group [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	3,996,000	4,276,000	15,571,000	13,759,000
Underground Group [Member]
Segment Reporting Information [Line Items]
Number of business units			2
Net sales to external customers	27,266,000	20,529,000	59,066,000	61,817,000
Gross profit	1,979,000	2,701,000	4,486,000	7,838,000
Gross profit (in hundredths)	7.30%	13.20%	7.60%	12.70%
Segment profit (loss)	(813,000)	(127,000)	(3,963,000)	(1,173,000)
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	(813,000)	(127,000)	(3,963,000)	(1,173,000)
Underground Group [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	0	50,000	2,298,000	1,008,000
All Others [Member]
Segment Reporting Information [Line Items]
Net sales to external customers	23,642,000	22,587,000	69,412,000	70,124,000
Gross profit	4,045,000	4,419,000	13,128,000	12,457,000
Gross profit (in hundredths)	17.10%	19.60%	18.90%	17.80%
Segment profit (loss)	(5,652,000)	(5,243,000)	(21,578,000)	(22,929,000)
Reconciliation of total segment profits to the Company's consolidated totals [Abstract]
Total segment profits	(5,652,000)	(5,243,000)	(21,578,000)	(22,929,000)
All Others [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	$ 0	$ 57,000	$ 0	$ 168,000