Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Numerator:
Income (loss) from continuing operations	$ 2,612	$ (24,988)	$ 15,549	$ (17,837)
Income from continuing operations attributable to non-controlling interest	(283)	(259)	(579)	(504)
Adjustment of estimated redemption value of non-controlling interest	0	276	0	0
Numerator for basic and diluted earnings per share from continuing operations - income (loss) from continuing operations attributable to Headwaters Incorporated	2,329	(24,971)	14,970	(18,341)
Numerator for basic and diluted earnings per share from discontinued operations - income (loss) from discontinued operations, net of income taxes	(228)	(210)	(444)	(277)
Numerator for basic and diluted earnings per share - net income (loss) attributable to Headwaters Incorporated	$ 2,101	$ (25,181)	$ 14,526	$ (18,618)
Denominator:
Denominator for basic earnings per share - weighted-average shares outstanding	73,818	73,555	73,804	73,501
Effect of dilutive securities - shares issuable upon exercise of options and SARs and vesting of restricted stock	1,523	0	1,549	0
Denominator for diluted earnings per share - weighted-average shares outstanding after assumed exercises and vesting	75,341	73,555	75,353	73,501
Basic income (loss) per share attributable to Headwaters Incorporated:
From continuing operations (in dollars per share)	$ 0.03	$ (0.34)	$ 0.21	$ (0.25)
From discontinued operations (in dollars per share)	0.00	0.00	(0.01)	0.00
Basic income (loss) per share (in dollars per share)	0.03	(0.34)	0.20	(0.25)
Diluted income (loss) per share attributable to Headwaters Incorporated:
From continuing operations (in dollars per share)	0.03	(0.34)	0.20	(0.25)
From discontinued operations (in dollars per share)	0.00	0.00	(0.01)	0.00
Diluted income (loss) per share (in dollars per share)	$ 0.03	$ (0.34)	$ 0.19	$ (0.25)