Summary of Operating Results and Certain Other Financial Data for Business Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2013	Feb. 29, 2012
Segment Reporting Information [Line Items]
NET SALES	$ 141,359	$ 121,894	$ 483,575	$ 435,696
Segment operating profit (loss)	7,698	(7,933)	25,180	(8,932)
Corporate	(10,339)	(9,880)	(30,967)	(22,038)
Interest	(7,227)	(8,512)	(22,462)	(26,810)
LOSS BEFORE INCOME TAXES FROM CONTINUING OPERATIONS	(9,868)	(26,325)	(28,249)	(57,780)
Depreciation, depletion and amortization			42,968	46,495
Capital expenditures	22,221	33,949	68,872	96,036
Cement Segment
Segment Reporting Information [Line Items]
Sales to external customers	71,288	55,020	239,406	192,717
Intersegment sales	9,277	10,451	29,807	35,625
Segment operating profit (loss)	9,849	(2,384)	24,328	(1,222)
Capital expenditures	13,803	29,911	54,588	69,800
Aggregates
Segment Reporting Information [Line Items]
Sales to external customers	25,439	17,663	94,738	66,168
Intersegment sales	5,378	4,952	17,272	15,613
Segment operating profit (loss)	2,111	(1,291)	9,629	2,494
Capital expenditures	927	1,352	3,528	20,715
Consumer Products
Segment Reporting Information [Line Items]
Sales to external customers	44,632	49,211	149,431	176,811
Intersegment sales	8	668	119	2,213
Segment operating profit (loss)	(4,262)	(4,258)	(8,777)	(10,204)
Capital expenditures	7,290	2,113	9,536	4,155
Intersegment Elimination
Segment Reporting Information [Line Items]
NET SALES	(14,663)	(16,071)	(47,198)	(53,451)
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	201	573	1,220	1,366
Cement
Segment Reporting Information [Line Items]
NET SALES	63,811	47,379	213,215	167,178
Stone, Sand And Gravel
Segment Reporting Information [Line Items]
NET SALES	16,641	11,878	60,638	44,410
Ready-Mix Concrete
Segment Reporting Information [Line Items]
NET SALES	44,821	37,464	149,403	138,265
Other products
Segment Reporting Information [Line Items]
NET SALES	2,025	12,080	7,540	40,778
Delivery Fees
Segment Reporting Information [Line Items]
NET SALES	14,061	13,093	52,779	45,065
Segment, Continuing Operations
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	14,096	14,718	41,956	45,330
Segment, Continuing Operations \| Cement Segment
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	8,395	8,723	25,288	26,547
Segment, Continuing Operations \| Aggregates
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	3,166	3,506	9,840	10,796
Segment, Continuing Operations \| Consumer Products
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	2,281	2,194	6,128	7,084
Segment, Continuing Operations \| Corporate
Segment Reporting Information [Line Items]
Depreciation, depletion and amortization	$ 254	$ 295	$ 700	$ 903

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

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The cost of borrowed funds accounted for as interest that was charged against earnings during the period.

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The aggregate amount of other expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating expense recognized during the period. Such amounts may include: (a) unusual costs, (b) loss on foreign exchange transactions, (c) losses on securities (net of profits), and (d) miscellaneous other expense items.

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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

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Amount of revenue from external customers for the reportable segment. Such disclosure is presented if the amount is: (a) included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

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Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

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