XML 101 R68.htm IDEA: XBRL DOCUMENT v2.4.1.9

Gain on Dispositions of Plant, Equipment and Timberlands - Summary for Sale of Timberlands and Other Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Proceeds	$ 5,072us-gaap_TimberRevenue	$ 1,947us-gaap_TimberRevenue	$ 10,272us-gaap_TimberRevenue
Gain	4,861us-gaap_GainLossOnSaleOfPropertyPlantEquipment	1,726us-gaap_GainLossOnSaleOfPropertyPlantEquipment	9,815us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Timberlands [Member]
Property, Plant and Equipment [Line Items]
Acres	2,753glt_AcresOfTimberland / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember	876glt_AcresOfTimberland / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember	4,830glt_AcresOfTimberland / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember
Proceeds	5,062us-gaap_TimberRevenue / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember	1,445us-gaap_TimberRevenue / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember	9,494us-gaap_TimberRevenue / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember
Gain	4,855us-gaap_GainLossOnSaleOfPropertyPlantEquipment / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember	1,410us-gaap_GainLossOnSaleOfPropertyPlantEquipment / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember	9,203us-gaap_GainLossOnSaleOfPropertyPlantEquipment / us-gaap_PropertyPlantAndEquipmentByTypeAxis = glt_TimberlandsMember
Other [Member]
Property, Plant and Equipment [Line Items]
Proceeds	10us-gaap_TimberRevenue / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember	502us-gaap_TimberRevenue / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember	778us-gaap_TimberRevenue / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember
Gain	$ 6us-gaap_GainLossOnSaleOfPropertyPlantEquipment / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember	$ 316us-gaap_GainLossOnSaleOfPropertyPlantEquipment / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember	$ 612us-gaap_GainLossOnSaleOfPropertyPlantEquipment / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember

X

- Definition

Acres of timberland.

+ References

No definition available.

+ Details

Name:	glt_AcresOfTimberland
Namespace Prefix:	glt_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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- Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Revenue from sale of timber, mill lumber, wood, and other wood products.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: