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Segment and Geographic Information - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2014
Customer
Dec. 31, 2013
Customer
Dec. 31, 2012
Customer
Segment Reporting, Revenue Reconciling Item [Line Items]      
Number of customers accounting for percentage of net sales 0glt_NumberOfCustomersAccountingForPercentageOfNetSales 0glt_NumberOfCustomersAccountingForPercentageOfNetSales 0glt_NumberOfCustomersAccountingForPercentageOfNetSales
Customers accounted for certain percentage in net sales 10.00%glt_EntityWideRevenueMajorCustomerPercentageThreshold 10.00%glt_EntityWideRevenueMajorCustomerPercentageThreshold 10.00%glt_EntityWideRevenueMajorCustomerPercentageThreshold
Advanced Airlaid Materials [Member]      
Segment Reporting, Revenue Reconciling Item [Line Items]      
Number of customers accounting for percentage of net sales 1glt_NumberOfCustomersAccountingForPercentageOfNetSales
/ us-gaap_StatementBusinessSegmentsAxis
= glt_AdvancedAirlaidMaterialsMember		 1glt_NumberOfCustomersAccountingForPercentageOfNetSales
/ us-gaap_StatementBusinessSegmentsAxis
= glt_AdvancedAirlaidMaterialsMember		 1glt_NumberOfCustomersAccountingForPercentageOfNetSales
/ us-gaap_StatementBusinessSegmentsAxis
= glt_AdvancedAirlaidMaterialsMember