Selected Quarterly Financial Data (Unaudited) - Schedule of Revisions to Previously Issued Quarterly Information (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
Gross profit	72,634	92,699	108,760	103,011	106,595	112,327	104,090	93,992	377,104		417,004		320,068
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 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]
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
Gross profit		91,519	109,769	105,549	105,271	113,734	103,679	93,615			416,299		320,476
Net income		10,419	23,850	22,569	22,732	25,496	22,075	24,194			94,495		112,664
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
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
Gross profit		1,180	(1,009)	(2,538)	1,324	(1,407)	411	377			705		(408)
Net income		1,169	(842)	(2,631)	615	(1,481)	(196)	(244)			(1,304)		(2,145)
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)

[1] See Note 4—Earnings Per Share.