Business Segments - Additional Information (Detail) (USD $)	9 Months Ended			1 Months Ended	9 Months Ended								3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Feb. 28, 2013 Segment	Feb. 29, 2012	Feb. 29, 2012 Normal Replacement And Upgrades To Sustain Existing Operations Amount Incurred To Acquire Aggregate Reserves	Jul. 31, 2011 Exchange of Productive Assets	Feb. 29, 2012 Crestmore Cement Plant	Feb. 28, 2013 Hunter Cement Plant	Feb. 29, 2012 Hunter Cement Plant	Feb. 29, 2012 Consumer Products Exchange of Productive Assets	Feb. 29, 2012 Cement	Feb. 29, 2012 Aggregates	Feb. 29, 2012 Ready-Mix Concrete	Feb. 29, 2012 Corporate	Feb. 28, 2013 Maximum	Feb. 29, 2012 Maximum	Feb. 28, 2013 Maximum	Feb. 29, 2012 Maximum	Feb. 28, 2013 Net Sales customer	Feb. 29, 2012 Net Sales customer	Feb. 28, 2013 Net Sales customer	Feb. 29, 2012 Net Sales customer
Segment Reporting Information [Line Items]
Number of operating business segments	3
Number of customers exceeding 10% threshold																	0	0	0	0
Sales percentage represented by major customers													10.00%	10.00%	10.00%	10.00%
Segment operating profit					$ 2,500,000
Gain (loss) on disposition of assets				2,100,000				2,100,000	2,500,000
Restructuring charges included in operating profit		2,000,000							1,100,000	400,000	500,000	1,200,000
Capital expenditure incurred for expansion	61,344,000	64,901,000				61,300,000	64,900,000
Capitalized interest paid						38,500,000	32,300,000
Upgrades of existing equipment and acquisitions	$ 17,752,000	$ 31,394,000	$ 18,000,000