Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Revisions to Previously Issued Income Statements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total revenue	$ 247,748	$ 276,839	$ 306,170	$ 300,494	$ 313,133	$ 316,171	$ 305,747	$ 283,105	$ 1,131,251		$ 1,218,156		$ 1,010,466
Cost of goods and services									754,147		801,152		690,398
Gross profit	72,634	92,699	108,760	103,011	106,595	112,327	104,090	93,992	377,104		417,004		320,068
Selling, general and administrative expense									276,014		264,947		221,407
Interest expense, net									39,301		27,648		863
Other expense, net									2,603		3,056		9,443
Income before income taxes									59,186		121,353		88,355
Provision for (benefit from) income taxes									6,226		28,162		(22,164)
Net income	(1,574)	11,588	23,008	19,938	23,347	24,015	21,879	23,950	52,960		93,191		110,519
Net income attributable to noncontrolling interest									796		454		930
Net income 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
Earnings per share attributable to Apergy:
Basic (in dollars per share)	$ (0.02)	$ 0.15	$ 0.30	$ 0.25	$ 0.30	$ 0.31	$ 0.28	$ 0.31	$ 0.67	[1]	$ 1.20	[1]	$ 1.42	[1]
Diluted (in dollars per share)	$ (0.02)	$ 0.15	$ 0.30	$ 0.25	$ 0.30	$ 0.31	$ 0.28	$ 0.31	$ 0.67	[1]	$ 1.19	[1]	$ 1.41	[1]
Comprehensive income									$ 51,829		$ 80,437		$ 117,760
Comprehensive income attributable to Apergy									51,033		79,983		116,830
Product revenue
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue									1,000,630		1,090,218		922,692
Other revenue
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue									$ 130,621		127,938		87,774
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total revenue		$ 278,381	$ 306,054	$ 301,691	$ 311,202	$ 316,468	$ 305,850	$ 283,126			1,216,646		1,010,466
Cost of goods and services											800,347		689,990
Gross profit		91,519	109,769	105,549	105,271	113,734	103,679	93,615			416,299		320,476
Selling, general and administrative expense											262,625		218,558
Interest expense, net											27,440		753
Other expense, net											2,943		10,377
Income before income taxes											123,291		90,788
Provision for (benefit from) income taxes											28,796		(21,876)
Net income		10,419	23,850	22,569	22,732	25,496	22,075	24,194			94,495		112,664
Net income attributable to noncontrolling interest											454		930
Net income attributable to Apergy		$ 10,225	$ 23,779	$ 22,287	$ 22,571	$ 25,264	$ 22,154	$ 24,052			$ 94,041		$ 111,734
Earnings per share attributable to Apergy:
Basic (in dollars per share)		$ 0.13	$ 0.31	$ 0.29	$ 0.29	$ 0.33	$ 0.29	$ 0.31			$ 1.22		$ 1.44
Diluted (in dollars per share)		$ 0.13	$ 0.31	$ 0.29	$ 0.29	$ 0.33	$ 0.28	$ 0.31			$ 1.21		$ 1.43
Comprehensive income											$ 81,741		$ 119,905
Comprehensive income attributable to Apergy											81,287		118,975
As Reported | Product revenue
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue											1,085,471		919,669
As Reported | Other revenue
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue											131,175		90,797
Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total revenue		$ (1,542)	$ 116	$ (1,197)	$ 1,931	$ (297)	$ (103)	$ (21)			1,510		0
Cost of goods and services											805		408
Gross profit		1,180	(1,009)	(2,538)	1,324	(1,407)	411	377			705		(408)
Selling, general and administrative expense											2,322		2,849
Interest expense, net											208		110
Other expense, net											113		(934)
Income before income taxes											(1,938)		(2,433)
Provision for (benefit from) income taxes											(634)		(288)
Net income		1,169	(842)	(2,631)	615	(1,481)	(196)	(244)			(1,304)		(2,145)
Net income attributable to noncontrolling interest											0		0
Net income attributable to Apergy		$ 1,169	$ (842)	$ (2,631)	$ 616	$ (1,303)	$ (338)	$ (279)			$ (1,304)		$ (2,145)
Earnings per share attributable to Apergy:
Basic (in dollars per share)		$ 0.02	$ (0.01)	$ (0.04)	$ 0.01	$ (0.02)	$ (0.01)	$ 0			$ (0.02)		$ (0.02)
Diluted (in dollars per share)		$ 0.02	$ (0.01)	$ (0.04)	$ 0.01	$ (0.02)	$ 0	$ 0			$ (0.02)		$ (0.02)
Comprehensive income											$ (1,304)		$ (2,145)
Comprehensive income attributable to Apergy											(1,304)		(2,145)
Adjustments | Product revenue
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue											4,747		3,023
Adjustments | Other revenue
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenue											$ (3,237)		$ (3,023)

[1] See Note 4—Earnings Per Share.