Condensed Consolidating Financial Information (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Revenue:
Light building products	$ 74,311	$ 62,677	$ 147,645	$ 132,386
Heavy construction materials	51,239	45,096	114,377	108,311
Energy technology	4,082	5,431	5,037	8,327
Total revenue	129,632	113,204	267,059	249,024
Cost of revenue:
Light building products	54,613	51,935	109,943	105,784
Heavy construction materials	41,380	37,509	88,478	85,861
Energy technology	2,074	2,683	2,631	4,473
Total cost of revenue	98,067	92,127	201,052	196,118
Gross profit	31,565	21,077	66,007	52,906
Operating expenses:
Amortization	5,298	5,606	10,803	11,153
Research and development	1,616	1,645	3,470	3,590
Selling, general and administrative	25,692	40,912	46,974	65,306
Restructuring costs	757	4,819	2,145	5,799
Total operating expenses	33,363	52,982	63,392	85,848
Operating income (loss)	(1,798)	(31,905)	2,615	(32,942)
Other income (expense):
Net interest expense	(13,527)	(82,595)	(25,983)	(99,490)
Other, net	(173)	1,848	(4,310)	2,822
Total other income (expense), net	(13,700)	(80,747)	(30,293)	(96,668)
Income (loss) from continuing operations before income taxes	(15,498)	(112,652)	(27,678)	(129,610)
Income tax benefit (provision)	(2,730)	(1,220)	(3,830)	(3,020)
Loss from continuing operations	(18,228)	(113,872)	(31,508)	(132,630)
Loss from discontinued operations, net of income taxes	(2,330)	(42,282)	(12,798)	(44,211)
Net loss	(20,558)	(156,154)	(44,306)	(176,841)
Guarantor Subsidiaries
Revenue:
Light building products	74,311	62,677	147,645	132,386
Heavy construction materials	51,239	45,096	114,377	108,311
Energy technology	4,082	5,431	5,037	8,327
Total revenue	129,632	113,204	267,059	249,024
Cost of revenue:
Light building products	54,613	51,935	109,943	105,784
Heavy construction materials	41,380	37,509	88,478	85,861
Energy technology	2,074	2,683	2,631	4,473
Total cost of revenue	98,067	92,127	201,052	196,118
Gross profit	31,565	21,077	66,007	52,906
Operating expenses:
Amortization	5,298	5,606	10,803	11,153
Research and development	1,616	1,645	3,470	3,590
Selling, general and administrative	19,622	36,414	37,791	56,510
Restructuring costs	757	4,819	2,145	4,819
Total operating expenses	27,293	48,484	54,209	76,072
Operating income (loss)	4,272	(27,407)	11,798	(23,166)
Other income (expense):
Net interest expense	(18)	(8)	(37)	6
Other, net	(173)	12	(443)	371
Total other income (expense), net	(191)	4	(480)	377
Income (loss) from continuing operations before income taxes	4,081	(27,403)	11,318	(22,789)
Income tax benefit (provision)	794	425	1,810	(380)
Loss from continuing operations	4,875	(26,978)	13,128	(23,169)
Loss from discontinued operations, net of income taxes	(2,330)	(42,282)	(12,798)	(44,211)
Net loss	2,545	(69,260)	330	(67,380)
Non-Guarantor Subsidiaries
Other income (expense):
Other, net		1,836	(5,892)	2,451
Total other income (expense), net		1,836	(5,892)	2,451
Income (loss) from continuing operations before income taxes		1,836	(5,892)	2,451
Income tax benefit (provision)	(116)	(677)	(943)	41
Loss from continuing operations	(116)	1,159	(6,835)	2,492
Net loss	(116)	1,159	(6,835)	2,492
Parent Company
Operating expenses:
Selling, general and administrative	6,070	4,498	9,183	8,796
Restructuring costs				980
Total operating expenses	6,070	4,498	9,183	9,776
Operating income (loss)	(6,070)	(4,498)	(9,183)	(9,776)
Other income (expense):
Net interest expense	(13,509)	(82,587)	(25,946)	(99,496)
Other, net			2,025
Total other income (expense), net	(13,509)	(82,587)	(23,921)	(99,496)
Income (loss) from continuing operations before income taxes	(19,579)	(87,085)	(33,104)	(109,272)
Income tax benefit (provision)	(3,408)	(968)	(4,697)	(2,681)
Loss from continuing operations	(22,987)	(88,053)	(37,801)	(111,953)
Net loss	$ (22,987)	$ (88,053)	$ (37,801)	$ (111,953)