Quarterly Financial Data (Unaudited) (Schedule Of Unaudited Quarterly Financial Data) (Details) (USD $) In Thousands	12 Months Ended			3 Months Ended							12 Months Ended	3 Months Ended																12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Jun. 30, 2011 Originally Reported [Member]	Mar. 31, 2011 Originally Reported [Member]	Dec. 31, 2010 Originally Reported [Member]	Sep. 30, 2010 Originally Reported [Member]	Jun. 30, 2010 Originally Reported [Member]	Mar. 31, 2010 Originally Reported [Member]	Dec. 31, 2009 Originally Reported [Member]	Sep. 30, 2010 Originally Reported [Member]	Sep. 30, 2011 Revised And Reported [Member]		Jun. 30, 2011 Revised And Reported [Member]		Mar. 31, 2011 Revised And Reported [Member]		Dec. 31, 2010 Revised And Reported [Member]		Sep. 30, 2010 Revised And Reported [Member]		Jun. 30, 2010 Revised And Reported [Member]		Mar. 31, 2010 Revised And Reported [Member]		Dec. 31, 2009 Revised And Reported [Member]		Sep. 30, 2011 Revised And Reported [Member]		Sep. 30, 2010 Revised And Reported [Member]
Net revenue	$ 591,954	$ 598,213	$ 608,395	$ 172,257	$ 127,135	$ 154,701	$ 194,718	$ 192,181	$ 128,154	$ 139,646	$ 654,699	$ 178,118	[1],[2],[3]	$ 162,360	[1],[2]	$ 115,041	[1],[2],[4]	$ 136,435	[1],[2]	$ 177,869	[1],[2],[5]	$ 173,814	[1],[2]	$ 115,734	[1],[2]	$ 130,796	[1],[2]	$ 591,954	[1],[2]	$ 598,213	[1],[2]
Gross profit	$ 149,923	$ 171,792	$ 161,051	$ 40,460	$ 17,542	$ 32,815	$ 51,440	$ 54,964	$ 27,526	$ 29,385	$ 163,315	$ 48,874	[1],[2],[3]	$ 45,691	[1],[2]	$ 22,914	[1],[2],[4]	$ 32,444	[1],[2]	$ 52,853	[1],[2],[5]	$ 54,494	[1],[2]	$ 30,206	[1],[2]	$ 34,239	[1],[2]	$ 149,923	[1],[2]	$ 171,792	[1],[2]

[1] Headwaters' revenue is seasonal, with higher revenues typically occurring in the third and fourth quarters than in the first and second quarters. As a result, profitability is also usually higher in the last half of the year than in the first half of the year.

[2] In the fourth quarter of 2011, Headwaters committed to a plan to sell its coal cleaning business and met all the criteria for presentation of this business as a discontinued operation (see Note 4). Accordingly, the results of Headwaters' coal cleaning operations have been presented as discontinued for all periods presented, which changed the amounts reported in the quarters shown in the table above for net revenue and gross profit. Also, as a result of significant restructuring costs incurred in the fourth quarter of 2011, Headwaters reclassified certain costs incurred in prior 2011 quarters to be consistent with the fourth quarter presentation (see Note 13). As a result of these two changes, net revenue and gross profit as reported in the table above are different from the amounts originally reported in Headwaters' 2010 Form 10-K and in Forms 10-Q for 2010 and 2011, as shown below.

[3] In the fourth quarter of 2011, Headwaters recorded an asset impairment charge of $35.0 million (see Note 6).

[4] In the second quarter of 2011, Headwaters recorded an asset impairment charge of $37.0 million (see Note 6), a litigation accrual for $15.0 million (see Note 14), and incremental interest expense related to the senior secured debt refinancing of $68.9 million (see Note 7).

[5] In the fourth quarter of 2010, Headwaters recorded an asset impairment charge of $34.5 million. (see Note 6).