Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 segment	Mar. 31, 2011	Sep. 30, 2011
Segment Reporting
Number of business segments			3
Segment reporting
Segment revenue	$ 129,632	$ 113,204	$ 267,059	$ 249,024
Depreciation and amortization	(13,014)	(13,894)	(26,196)	(26,464)
Operating income (loss)	(1,798)	(31,905)	2,615	(32,942)
Net interest expense	(13,527)	(82,595)	(25,983)	(99,490)
Other income (expense), net	(173)	1,848	(4,310)	2,822
Income tax 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)
Capital expenditures	5,213	6,940	11,832	14,643
Segment assets	659,923	766,815	659,923	766,815	728,237
Light Building Products
Segment reporting
Segment revenue	74,311	62,677	147,645	132,386
Depreciation and amortization	(8,908)	(9,823)	(17,972)	(18,363)
Operating income (loss)	2,108	(12,989)	2,881	(15,237)
Capital expenditures	4,272	4,365	8,873	10,475
Segment assets	273,122	303,077	273,122	303,077
Heavy Construction Materials
Segment reporting
Segment revenue	51,239	45,096	114,377	108,311
Depreciation and amortization	(3,493)	(3,463)	(7,024)	(6,904)
Operating income (loss)	2,870	301	11,624	8,131
Capital expenditures	640	829	1,424	1,127
Segment assets	295,323	301,166	295,323	301,166
Energy Technology
Segment reporting
Segment revenue	4,082	5,431	5,037	8,327
Depreciation and amortization	(572)	(581)	(1,144)	(1,141)
Operating income (loss)	(706)	(14,719)	(2,707)	(16,060)
Capital expenditures	112	1,746	1,328	3,041
Capital expenditures related to discontinued operations	0	1,732	1,116	2,987
Segment assets	46,868	102,746	46,868	102,746
Segment assets related to discontinued operations	30,143		30,143
Corporate
Segment reporting
Segment revenue	0	0	0	0
Depreciation and amortization	(41)	(27)	(56)	(56)
Operating income (loss)	(6,070)	(4,498)	(9,183)	(9,776)
Capital expenditures	189	0	207	0
Segment assets	$ 44,610	$ 59,826	$ 44,610	$ 59,826