XML 101 R84.htm IDEA: XBRL DOCUMENT
v3.20.2

Commitments, Contingencies and Legal Proceedings - Additional Information (Detail) $ in Thousands | 1 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jan. 31, 2019 USD ($) | Jun. 30, 2020 USD ($) Operable_Unit | Dec. 31, 2019 USD ($)
Commitments Contingencies And Litigation [Line Items] |  |  |
Number of operable units | Operable_Unit |  | 5 |
Term of agreement with third party for monitoring and maintenance in OU1-OU4a |  | 30 years |
Difference recorded in escrow account |  | $ 500 |
Total amount available in escrow account |  | 9,000 |
Reserve for Environmental liabilities, current portion |  | 5,000 | $ 9,000
Other Long-Term Liabilities [Member] |  |  |
Commitments Contingencies And Litigation [Line Items] |  |  |
Reserve for Environmental liabilities, remaining portion |  | $ 14,700 |
Minimum [Member] |  |  |
Commitments Contingencies And Litigation [Line Items] |  |  |
Period over which cash expenditure to be incurred for monitoring activities |  | 30 years |
Glatfelter Consent Decree [Member] |  |  |
Commitments Contingencies And Litigation [Line Items] |  |  |
Payments for governments unreimbursed past costs | $ 20,500 |  | $ 20,500
OU2-5 [Member] |  |  |
Commitments Contingencies And Litigation [Line Items] |  |  |
Expected cleanup work continuation year |  | in 2020 |

X
- Definition Accrued environmental loss contingencies remaining amount. + References No definition available. + Details
Name: | glt_AccruedEnvironmentalLossContingenciesRemainingAmount
Namespace Prefix: | glt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount available in escrow account. + References No definition available. + Details
Name: | glt_AmountAvailableInEscrowAccount
Namespace Prefix: | glt_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Commitments Contingencies And Litigation [Line Items] + References No definition available. + Details
Name: | glt_CommitmentsContingenciesAndLitigationLineItems
Namespace Prefix: | glt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Difference recorded in escrow account. + References No definition available. + Details
Name: | glt_DifferenceRecordedInEscrowAccount
Namespace Prefix: | glt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Expected cleanup work continuation period description. + References No definition available. + Details
Name: | glt_ExpectedCleanupWorkContinuationPeriodDescription
Namespace Prefix: | glt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The specific areas of the site into which the contaminated area has been separated by the US EPA. + References No definition available. + Details
Name: | glt_NumberOfOperableUnits
Namespace Prefix: | glt_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Payments for governments unreimbursed past costs. + References No definition available. + Details
Name: | glt_PaymentsForGovernmentsUnreimbursedPastCosts
Namespace Prefix: | glt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Period over which cash expenditure to be incurred. + References No definition available. + Details
Name: | glt_PeriodOverWhichCashExpenditureToBeIncurred
Namespace Prefix: | glt_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term of agreement with third party. + References No definition available. + Details
Name: | glt_TermOfAgreementWithThirdParty
Namespace Prefix: | glt_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- 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 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.20) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 10 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=121566466&loc=d3e6911-107765 + Details
Name: | us-gaap_AccruedEnvironmentalLossContingenciesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OtherCommitmentsAxis=glt_GlatfelterConsentDecreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=glt_DownstreamMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |