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- Definition

Selling, General, Administrative and Interest Expense

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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- 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.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details) $ / shares in Units, $ in Thousands		3 Months Ended								12 Months Ended
	May 09, 2018	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Property, Plant and Equipment [Line Items]
Conversion ratio	0.5
Research and development expense										$ 12,900	$ 16,000	$ 18,500
Reduction in depreciation										(68,557)	(72,569)	(59,161)
Net income (loss) attributable to Apergy		$ (1,823)	$ 11,394	$ 22,937	$ 19,656	$ 23,187	$ 23,961	$ 21,816	$ 23,773	$ 52,164	92,737	109,589
Minimum \| Building and improvements
Property, Plant and Equipment [Line Items]
Useful life										5 years
Minimum \| Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful life										1 year
Minimum \| Software
Property, Plant and Equipment [Line Items]
Useful life										3 years
Minimum \| Other intangible assets
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset, useful life (in years)										5 years
Maximum \| Building and improvements
Property, Plant and Equipment [Line Items]
Useful life										31 years 6 months
Maximum \| Machinery and equipment
Property, Plant and Equipment [Line Items]
Useful life										7 years
Maximum \| Software
Property, Plant and Equipment [Line Items]
Useful life										10 years
Maximum \| Other intangible assets
Property, Plant and Equipment [Line Items]
Finite-lived intangible asset, useful life (in years)										15 years
Adjustments
Property, Plant and Equipment [Line Items]
Net income (loss) attributable to Apergy			1,169	(842)	(2,631)	616	(1,303)	(338)	(279)		(1,304)	(2,145)
Selling, general, administrative and interest expense											3,100	2,000
As Reported
Property, Plant and Equipment [Line Items]
Net income (loss) attributable to Apergy			$ 10,225	$ 23,779	$ 22,287	$ 22,571	$ 25,264	$ 22,154	$ 24,052		$ 94,041	$ 111,734
Service Life
Property, Plant and Equipment [Line Items]
Reduction in depreciation										$ 8,800
Net income (loss) attributable to Apergy										$ 6,700
Earnings per share, basic and diluted (in dollars per share) \| $ / shares										$ 0.09
Production & Automation Technologies \| Service Life
Property, Plant and Equipment [Line Items]
Useful life										5 years	3 years