Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013 segment	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting
Number of business segments									3
Segment reporting
Segment revenue	$ 214,985	$ 197,030	$ 140,988	$ 149,573	$ 190,107	$ 175,621	$ 129,632	$ 137,427	$ 702,576	$ 632,787	$ 587,964
Depreciation and amortization									(52,317)	(51,481)	(54,008)
Operating income (loss)									54,411	34,403	(12,165)
Net interest expense									(42,566)	(52,678)	(126,252)
Other income (expense), net									364	(7,493)	4,314
Income tax benefit (provision)									(3,924)	(661)	171
Income (loss) from continuing operations									8,285	(26,429)	(133,932)
Loss from discontinued operations, net of income taxes									(1,148)	(35,819)	(95,989)
Net income (loss)	10,253	11,016	(8,260)	(5,872)	(4,906)	(13,036)	(20,558)	(23,748)	7,137	(62,248)	(229,921)
Capital expenditures									29,119	26,447	27,381
Segment assets	724,009				680,937				724,009	680,937	728,237
Light Building Products
Segment reporting
Segment revenue									394,324	339,632	314,062
Depreciation and amortization									(37,065)	(35,724)	(37,747)
Operating income (loss)									34,194	25,553	(14,751)
Capital expenditures									21,455	17,707	14,862
Segment assets	306,686				271,554				306,686	271,554	292,411
Heavy Construction Materials
Segment reporting
Segment revenue									293,000	281,672	253,300
Depreciation and amortization									(12,809)	(13,322)	(13,847)
Operating income (loss)									43,519	40,254	31,304
Capital expenditures									4,851	5,240	2,696
Segment assets	358,684				338,753				358,684	338,753	298,584
Energy Technology
Segment reporting
Segment revenue									15,252	11,483	20,602
Depreciation and amortization									(2,153)	(2,287)	(2,327)
Operating income (loss)									(1,939)	(6,045)	(14,387)
Capital expenditures									634	1,472	9,823
Segment assets	34,509				36,377				34,509	36,377	101,645
Corporate
Segment reporting
Segment revenue									0	0	0
Depreciation and amortization									(290)	(148)	(87)
Operating income (loss)									(21,363)	(25,359)	(14,331)
Capital expenditures									2,179	2,028	0
Segment assets	$ 24,130				$ 34,253				$ 24,130	$ 34,253	$ 35,597