Business Segments (Net Sales By Product Line) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net Sales	$ 426,707	$ 442,784	$ 732,951	$ 738,345
Aggregates [Member]
Net Sales	343,002	368,646	579,227	605,604
Asphalt [Member]
Net Sales	18,015	13,731	30,412	23,061
Ready Mixed Concrete [Member]
Net Sales	7,627	6,877	12,941	12,502
Road Paving [Member]
Net Sales	7,186	4,368	9,408	6,026
Other Product Line [Member]
Net Sales	1,277	1,273	2,222	1,537
Total Aggregates Business [Member]
Net Sales	377,107	394,895	634,210	648,730
Magnesia Based Chemicals [Member]
Net Sales	34,145	33,221	69,305	59,997
Dolomitic Lime [Member]
Net Sales	15,103	14,230	28,882	28,928
Others [Member]
Net Sales	352	438	554	690
Specialty Products [Member]
Net Sales	$ 49,600	$ 47,889	$ 98,741	$ 89,615