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Condensed Consolidating Financial Statements - Additional Information (Detail) | Mar. 31, 2018 | Oct. 03, 2012
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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%

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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