Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator:
Income (loss) from continuing operations	$ 11,124	$ 9,248	$ (517)	$ (4,909)
Net income attributable to non-controlling interest	(389)	0	(619)	0
Fair value adjustment of non-controlling interest	(158)	0	(158)	0
Numerator for basic and diluted earnings per share from continuing operations - income (loss) from continuing operations attributable to Headwaters Incorporated	10,577	9,248	(1,294)	(4,909)
Numerator for basic and diluted earnings per share from discontinued operations - income (loss) from discontinued operations, net of income taxes	(231)	1,768	(106)	1,793
Numerator for basic and diluted earnings per share - net income (loss) attributable to Headwaters Incorporated	$ 10,346	$ 11,016	$ (1,400)	$ (3,116)
Denominator:
Denominator for basic earnings per share - weighted-average shares outstanding	73,206	72,892	73,131	69,195
Effect of dilutive securities - shares issuable upon exercise of options and SARs and vesting of restricted stock	1,380	1,247	0	0
Denominator for diluted earnings per share - weighted-average shares outstanding after assumed exercises and vesting	74,586	74,139	73,131	69,195
Basic and diluted income (loss) per share from continuing operations (in dollars per share)	$ 0.14	$ 0.13	$ (0.02)	$ (0.07)
Basic and diluted income (loss) per share from discontinued operations (in dollars per share)	$ 0.00	$ 0.02	$ 0.00	$ 0.02
Earnings (loss) per share, basic and diluted, total (in dollars per share)	$ 0.14	$ 0.15	$ (0.02)	$ (0.05)
Stock Appreciation Rights S A R S [Member]
Statement
Anti-dilutive securities not considered in diluted EPS calculation (in shares)	691	775	3,836	2,877
Employee And Nonemployee Stock Option [Member]
Statement
Anti-dilutive securities not considered in diluted EPS calculation (in shares)	377	893	530	1,002
Restricted Stock [Member]
Statement
Anti-dilutive securities not considered in diluted EPS calculation (in shares)	0	0	253	140

Net income available to common stockholders after temporary equity accretion adjustments.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, and noncontrolling interest.

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The amount of net income (loss) from continuing operations per each basic and diluted share of common stock or unit when the per share amount is the same for both basic and diluted shares.

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Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Per basic and diluted share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation and gain (loss) from the disposal of the discontinued operation, when the per share amount is the same.

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Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

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Amount of decrease to net income for accretion of temporary equity to its redemption value to derive net income apportioned to common stockholders.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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