Costs of participating in potentially responsible parties group.

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- Definition

Environmental legal indemnification expense.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Loss contingency number of states new claims filed.

+ References

No definition available.

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- Definition

Net present value of selected remedy estimation.

+ References

No definition available.

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- Definition

The number of acquired plant sites where environmental remediation liabilities have been recorded for soil and groundwater contamination which occurred prior to acquisition.

+ References

No definition available.

+ Details

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- Definition

Number of potentially responsible parties.

+ References

No definition available.

+ Details

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- Definition

Number of sites listed on national priorities list.

+ References

No definition available.

+ Details

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- Definition

Undiscounted cost of selected remedy estimation.

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
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-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

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- Definition

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable in twelve months or in the next operating cycle if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Paragraph 1
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of loss contingency liability.

+ References

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- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Number of plaintiffs that have filed claims pertaining to a loss contingency.

+ References

No definition available.

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- Definition

Number of pending claims pertaining to a loss contingency.

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- Definition

Amount of the estimated recovery from third parties recorded in the period for an individual site that reduces environmental remediation expense.

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Commitments and Contingent Liabilities - Additional Information (Detail)	1 Months Ended	6 Months Ended	12 Months Ended
	Jul. 31, 2004 USD ($)	Jun. 30, 2018 USD ($) State Plaintiff Case site Party Plant	Dec. 31, 2017 USD ($) Plaintiff Case	Dec. 31, 2016 USD ($)
Loss Contingencies [Line Items]
Number of states with new claims filed \| State		2
Number of plaintiffs \| Plaintiff		85	87
Environmental remediation and regulation liability		$ 13,600,000	$ 13,900,000	$ 12,900,000
Accrued liability for environmental matters, current		4,500,000	$ 5,100,000
Portland Harbor and Newark Bay CERCLA sites [Member]
Loss Contingencies [Line Items]
Costs of participating in PRP group		$ 2,100,000
Beazer East [Member]
Loss Contingencies [Line Items]
Environmental legal indemnification expense	$ 7,000,000
Sites listed on National Priorities List \| site		1
Compensatory Damages [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		47
Punitive Damages [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		43
Indemnification Agreement [Member] \| Beazer East [Member]
Loss Contingencies [Line Items]
Environmental remediation costs paid by others, per year		$ 10,000,000
Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		47	48
Reserve for legal proceedings		$ 0
Pennsylvania [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		46
Pennsylvania [Member] \| Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		46
Tennessee [Member] \| Coal Tar Pitch Cases [Member]
Loss Contingencies [Line Items]
Number of cases \| Case		1
Compensatory damages		$ 15,000,000
Oregon [Member] \| Portland Harbor CERCLA site [Member]
Loss Contingencies [Line Items]
Number of potential responsible parties \| Party		80
Net present value of selected remedy estimation		$ 1,100,000,000
Undiscounted cost of selected remedy estimation		1,700,000,000
United States [Member] \| Performance Chemicals [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability		$ 4,900,000
Number of plant sites \| Plant		2
United States [Member] \| Utility and Industrial Products [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability		$ 1,900,000
Number of plant sites \| Plant		1
United Kingdom And Australia [Member] \| Performance Chemicals [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability		$ 2,600,000
Number of plant sites \| Plant		2
Australia [Member] \| Continental Carbon facility [Member]
Loss Contingencies [Line Items]
Environmental remediation and regulation liability		$ 700,000