Net Sales and Gross Profit by Line of Business (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Product Information [Line Items]
Net Sales	$ 1,005,218	$ 917,942	$ 2,487,342	$ 1,899,557
Gross profit (loss)	262,505	195,593	536,918	357,030
Operating Segments
Product Information [Line Items]
Net Sales	837,441	749,749	2,003,383	1,612,095
Gross profit (loss)	211,780	152,158	405,011	271,489
Operating Segments | Cement
Product Information [Line Items]
Net Sales	110,519	109,521	307,489	109,521
Gross profit (loss)	38,244	24,194	87,642	24,194
Operating Segments | Magnesia Specialties
Product Information [Line Items]
Net Sales	57,258	58,672	176,470	177,941
Gross profit (loss)	19,391	20,043	60,793	62,192
Corporate
Product Information [Line Items]
Gross profit (loss)	(6,910)	(802)	(16,528)	(845)
Aggregates
Product Information [Line Items]
Net Sales	529,993	478,834	1,343,821	1,164,692
Gross profit (loss)	166,166	119,277	344,857	229,471
Asphalt
Product Information [Line Items]
Net Sales	26,817	26,873	55,358	59,998
Gross profit (loss)	10,794	7,356	13,644	10,799
Ready Mixed Concrete
Product Information [Line Items]
Net Sales	209,608	183,715	486,931	274,103
Gross profit (loss)	23,557	18,628	34,981	28,554
Road Paving
Product Information [Line Items]
Net Sales	71,023	60,327	117,273	113,302
Gross profit (loss)	$ 11,263	$ 6,897	$ 11,529	$ 2,665