Summary of Asset Used in Each of Business Segments (Detail) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2013	May 31, 2013
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	$ 1,625,798	$ 1,635,825
Segment, Continuing Operations
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	1,625,798	1,635,825
Segment, Continuing Operations | Cement Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	1,167,264	1,174,879
Segment, Continuing Operations | Aggregates
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	164,609	168,255
Segment, Continuing Operations | Consumer Products
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	197,500	182,839
Segment, Continuing Operations | Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Identifiable assets	$ 96,425	$ 109,852