Net Sales and Gross Profit by Line of Business (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Product Information [Line Items]
Net Sales	$ 631,876	$ 379,678
Gross profit (loss)	74,261	25,835
Operating Segments
Product Information [Line Items]
Net Sales	631,876	379,678
Operating Segments | Corporate
Product Information [Line Items]
Gross profit (loss)	(3,629)	(507)
Aggregates
Product Information [Line Items]
Net Sales	332,214	263,885
Gross profit (loss)	41,417	10,051
Asphalt
Product Information [Line Items]
Net Sales	9,645	10,498
Gross profit (loss)	(1,463)	(1,426)
Ready Mixed Concrete
Product Information [Line Items]
Net Sales	127,572	38,009
Gross profit (loss)	2,084	2,944
Road Paving
Product Information [Line Items]
Net Sales	7,126	9,938
Gross profit (loss)	(3,311)	(3,982)
Aggregates Business
Product Information [Line Items]
Net Sales	476,557	322,330
Gross profit (loss)	38,727	7,587
Cement
Product Information [Line Items]
Net Sales	96,565
Gross profit (loss)	18,985
Magnesia Specialties
Product Information [Line Items]
Net Sales	58,754	57,348
Gross profit (loss)	$ 20,178	$ 18,755