Acquisitions and Divestitures (Details) (USD $)	0 Months Ended	3 Months Ended					9 Months Ended
	Oct. 03, 2011 facility segment	Sep. 30, 2011 facility segment	Mar. 31, 2011 facility Year	Sep. 30, 2010 facility		Mar. 31, 2010 facility	Sep. 30, 2011	Dec. 31, 2010
Held for Sale
Current assets		$ 2,644,000		$ 3,729,000			$ 2,644,000	$ 3,460,000
Property, plant & equipment, net		20,934,000		10,709,000			20,934,000	9,625,000
Other assets		3,305,000		144,000			3,305,000	122,000
Total assets held for sale		26,883,000		14,582,000	[1]		26,883,000	13,207,000
Current liabilities		0		460,000			0	116,000
Other liabilities		1,474,000		0			1,474,000	0
Total liabilities of assets held for sale		1,474,000		460,000	[1]		1,474,000	116,000
Acquisitions and Divestitures (Textuals)
Number of ready-mixed concrete facilities acquired			10	12
Number of shares of common stock valued at the closing date			432,407
Closing date price			$ 42.85
Total consideration net of cash acquired			18,529,000	35,404,000
Number of shares issued to seller			368,527
Number of shares retained to fulfill certain working capital adjustments and indemnification obligations			63,880
Amortizable intangible assets recognized			6,419,000
Estimated weighted-average period intangible assets are to be amortized			20
Number of aggregates facilities sold		4				3
Cash proceeds from divestiture		61,774,000				42,750,000
Gain recognized on divested assets		39,659,000				39,479,000
Goodwill included in book value of assets		10,300,000					10,300,000
Number of aggregates facilities acquired	3
Cash paid for acquiring facilities	$ 10,000,000
Number of aggregates facilities divested	2
Number of asphalt mix facilities divested	1
Number of ready-mixed concrete facilities divested	1

[1] As Restated, See Note 1