Condensed Consolidating Financial Statements - Additional Information (Detail)	Jun. 30, 2018	Oct. 03, 2012
PHG Tea Leaves, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Percentage owned in domestic subsidiaries	100.00%
Mollanvick, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Percentage owned in domestic subsidiaries	100.00%
Glatfelter Holdings, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage owned in domestic subsidiaries	100.00%
Glatfelter Composite Fibers N. A., Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Percentage owned in domestic subsidiaries	100.00%
Glatfelter Advanced Materials N.A., Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Percentage owned in domestic subsidiaries	100.00%
5.375% Notes [Member]
Schedule of Equity Method Investments [Line Items]
Percent on aggregate principal amount of outstanding	5.375%	5.375%