Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statement Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Nov. 30, 2011	Nov. 30, 2010
Net cash provided (used) by operating activities	$ 12,487	$ 10,026
Capital expenditures - expansions	(35,966)	(11,198)
Capital expenditures - other	(26,300)	(12,201)
Proceeds from asset disposals	1,649	3,037
Investments in life insurance contracts	2,989	3,704
Other - net	(128)	(859)
Net cash used by investing activities	(57,756)	(17,517)
Long-term borrowings		650,000
Debt retirements	(36)	(561,568)
Debt issuance costs	(1,732)	(12,426)
Stock option exercises	158	464
Common dividends paid	(2,091)	(4,172)
Net cash provided (used) by financing activities	(3,701)	72,298
Increase (decrease) in cash and cash equivalents	(48,970)	64,807
Cash and cash equivalents at beginning of period	116,432	74,946
Cash and cash equivalents at end of period	67,462	139,753
Texas Industries, Inc. [Member]
Net cash provided (used) by operating activities	(34,917)	(25,335)
Investments in life insurance contracts	2,989	3,704
Net cash used by investing activities	2,989	3,704
Long-term borrowings		650,000
Debt retirements		(561,394)
Debt issuance costs	(1,732)	(12,426)
Stock option exercises	158	464
Common dividends paid	(2,091)	(4,172)
Net intercompany financing activities	(12,561)	15,384
Net cash provided (used) by financing activities	(16,226)	87,856
Increase (decrease) in cash and cash equivalents	(48,154)	66,225
Cash and cash equivalents at beginning of period	113,898	72,492
Cash and cash equivalents at end of period	65,744	138,717
Guarantor Subsidiaries [Member]
Net cash provided (used) by operating activities	47,404	35,361
Capital expenditures - expansions	(35,966)	(11,198)
Capital expenditures - other	(26,300)	(12,201)
Proceeds from asset disposals	1,649	3,037
Other - net	(128)	(859)
Net cash used by investing activities	(60,745)	(21,221)
Debt retirements	(36)	(174)
Net intercompany financing activities	12,561	(15,384)
Net cash provided (used) by financing activities	12,525	(15,558)
Increase (decrease) in cash and cash equivalents	(816)	(1,418)
Cash and cash equivalents at beginning of period	2,534	2,454
Cash and cash equivalents at end of period	$ 1,718	$ 1,036