Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Changes in the carrying amount of goodwill by reportable segment
Goodwill, gross carrying amount, beginning balance		$ 3,349,680	$ 3,348,964
Goodwill of acquired businesses			716
Goodwill of divested businesses	(10,300)	(10,300)
Goodwill, gross carrying amount, ending balance		3,349,680	3,349,680	3,348,964
Goodwill, accumulated impairment losses, beginning balance		(252,664)	(252,664)
Goodwill impairment loss		0	0	0
Goodwill, accumulated impairment losses, ending balance		(252,664)	(252,664)	(252,664)
Goodwill, net of accumulated impairment losses, beginning balance		3,097,016	3,096,300
Goodwill, net of accumulated impairment losses, ending balance		3,086,716	3,097,016	3,096,300
Aggregates [Member]
Changes in the carrying amount of goodwill by reportable segment
Goodwill, gross carrying amount, beginning balance		3,005,383	3,004,667
Goodwill of acquired businesses			716
Goodwill of divested businesses		(10,300)
Goodwill, gross carrying amount, ending balance		2,995,083	3,005,383
Goodwill, accumulated impairment losses, beginning balance		0	0
Goodwill impairment loss		0	0
Goodwill, accumulated impairment losses, ending balance		0	0
Goodwill, net of accumulated impairment losses, beginning balance		3,005,383	3,004,667
Goodwill, net of accumulated impairment losses, ending balance		2,995,083	3,005,383
Concrete [Member]
Changes in the carrying amount of goodwill by reportable segment
Goodwill, gross carrying amount, beginning balance		0	0
Goodwill of acquired businesses			0
Goodwill of divested businesses		0
Goodwill, gross carrying amount, ending balance		0	0
Goodwill, accumulated impairment losses, beginning balance		0	0
Goodwill impairment loss		0	0
Goodwill, accumulated impairment losses, ending balance		0	0
Goodwill, net of accumulated impairment losses, beginning balance		0	0
Goodwill, net of accumulated impairment losses, ending balance		0	0
Asphalt Mix [Member]
Changes in the carrying amount of goodwill by reportable segment
Goodwill, gross carrying amount, beginning balance		91,633	91,633
Goodwill of acquired businesses			0
Goodwill of divested businesses		0
Goodwill, gross carrying amount, ending balance		91,633	91,633
Goodwill, accumulated impairment losses, beginning balance		0	0
Goodwill impairment loss		0	0
Goodwill, accumulated impairment losses, ending balance		0	0
Goodwill, net of accumulated impairment losses, beginning balance		91,633	91,633
Goodwill, net of accumulated impairment losses, ending balance		91,633	91,633
Cement [Member]
Changes in the carrying amount of goodwill by reportable segment
Goodwill, gross carrying amount, beginning balance		252,664	252,664
Goodwill of acquired businesses			0
Goodwill of divested businesses		0
Goodwill, gross carrying amount, ending balance		252,664	252,664
Goodwill, accumulated impairment losses, beginning balance		(252,664)	(252,664)
Goodwill impairment loss		0	0
Goodwill, accumulated impairment losses, ending balance		(252,664)	(252,664)
Goodwill, net of accumulated impairment losses, beginning balance		0	0
Goodwill, net of accumulated impairment losses, ending balance		$ 0	$ 0