Merger with Deltic (Summary of Unaudited Pro Forma Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Combinations [Abstract]
Net sales	$ 268,233	$ 218,582	$ 506,793	$ 421,478
Net earnings attributable to PotlatchDeltic common shareholders	$ 47,225	$ 20,984	$ 80,928	$ 33,829
Basic earnings per share attributable to PotlatchDeltic common Shareholders	$ 0.71	$ 0.32	$ 1.22	$ 0.51
Diluted earnings per share attributable to PotlatchDeltic common shareholders	$ 0.71	$ 0.31	$ 1.21	$ 0.51

Per basic share amount of pro forma income from continuing operations, after tax, as if the business combination had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Per diluted share amount of pro forma income from continuing operations, after tax, as if the business combination had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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