XML 13 R39.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Gains on Dispositions of Plant, Equipment and Timberlands, Net - Summary for Sale of Timberlands and Other Assets (Detail) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2015 USD ($) | Jun. 30, 2014 USD ($) | Jun. 30, 2015 USD ($) a | Jun. 30, 2014 USD ($) a
Property, Plant and Equipment [Line Items] |  |  |  |
Proceeds |  |  | $ 3,051 | $ 2,360
Gain | $ 111 | $ 1,482 | $ 2,765 | $ 2,291
Timberlands [Member] |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |
Acres | a |  |  | 1,398 | 935
Proceeds |  |  | $ 2,794 | $ 2,355
Gain |  |  | 2,705 | 2,290
Other [Member] |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |
Proceeds |  |  | 257 | 5
Gain |  |  | $ 60 | $ 1

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=56944662&loc=d3e3602-108585 + Details
Name: | us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- 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
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
Name: | us-gaap_TimberRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=glt_TimberlandsMember
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: |