Condensed Consolidating Financial Information - Consolidated Cash Flows (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	Jun. 30, 2019	Oct. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided (required) by operating activities			$ 155,899	$ 163,900	$ 76,050
Cash provided (required) by investing activities:
Capital expenditures			(39,780)	(57,918)	(36,654)
Proceeds from sale of property, plant and equipment			4,598	1,187	3,547
Proceeds from (payment on) sale of businesses	$ (2,200)		(2,194)
Proceeds from (payment on) sale of businesses		$ 2,500		2,473	0
Acquisition (net of cash and cash equivalents acquired)			(12,500)	0	(8,842)
Purchase price adjustments on acquisition			0	53	0
Net cash required by investing activities			(49,876)	(54,205)	(41,949)
Cash provided (required) by financing activities:
Proceeds from long-term debt, net of discounts			36,500	713,963	0
Payment of debt issue costs			0	(16,006)	0
Repayment of long-term debt			(141,500)	(45,000)	(599)
Advances due to (from) affiliates			0	0
Distributions to Dover Corporation, net			0	(736,557)	(31,192)
Distribution to noncontrolling interest			0	(2,720)	(1,212)
Payment of capital lease obligations			(5,555)	(4,518)	(3,690)
Payments related to taxes withheld on stock-based compensation			(1,848)	0	0
Net cash required by financing activities			(112,403)	(90,838)	(36,693)
Effect of exchange rate changes on cash and cash equivalents			(162)	(737)	277
Net increase (decrease) in cash and cash equivalents			(6,542)	18,120	(2,315)
Cash and cash equivalents at beginning of period			41,832	23,712	26,027
Cash and cash equivalents at end of period			35,290	41,832	23,712
Adjustments and eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided (required) by operating activities				(999)	67
Cash provided (required) by investing activities:
Capital expenditures			0	0	0
Proceeds from sale of property, plant and equipment			0	0	0
Proceeds from (payment on) sale of businesses			0
Proceeds from (payment on) sale of businesses				0
Acquisition (net of cash and cash equivalents acquired)			0		0
Purchase price adjustments on acquisition				0
Net cash required by investing activities			0	0	0
Cash provided (required) by financing activities:
Proceeds from long-term debt, net of discounts			0	0
Payment of debt issue costs				0
Repayment of long-term debt			0	0	0
Distributions to Dover Corporation, net				999	(67)
Distribution to noncontrolling interest				0	0
Payment of capital lease obligations			0	0	0
Payments related to taxes withheld on stock-based compensation			0
Net cash required by financing activities				999	(67)
Effect of exchange rate changes on cash and cash equivalents			0	0	0
Net increase (decrease) in cash and cash equivalents			0	0	0
Cash and cash equivalents at beginning of period			0	0	0
Cash and cash equivalents at end of period			0	0	0
Apergy Corporation
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided (required) by operating activities			(48,970)	(51,728)	0
Cash provided (required) by investing activities:
Capital expenditures			0	0	0
Proceeds from sale of property, plant and equipment			0	0	0
Proceeds from (payment on) sale of businesses			0
Proceeds from (payment on) sale of businesses				0
Acquisition (net of cash and cash equivalents acquired)			0		0
Purchase price adjustments on acquisition				0
Net cash required by investing activities			0	0	0
Cash provided (required) by financing activities:
Proceeds from long-term debt, net of discounts			36,500	713,963
Payment of debt issue costs				(16,006)
Repayment of long-term debt			(141,500)	(45,000)	0
Advances due to (from) affiliates			153,970	(600,802)
Distributions to Dover Corporation, net				(319)	0
Distribution to noncontrolling interest				0	0
Payment of capital lease obligations			0	0	0
Payments related to taxes withheld on stock-based compensation			0
Net cash required by financing activities			48,970	51,836	0
Effect of exchange rate changes on cash and cash equivalents			0	0	0
Net increase (decrease) in cash and cash equivalents			0	108	0
Cash and cash equivalents at beginning of period			108	0	0
Cash and cash equivalents at end of period			108	108	0
Subsidiary Guarantors
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided (required) by operating activities			204,877	200,907	64,422
Cash provided (required) by investing activities:
Capital expenditures			(37,725)	(55,070)	(35,008)
Proceeds from sale of property, plant and equipment			4,580	1,127	3,433
Proceeds from (payment on) sale of businesses			(2,194)
Proceeds from (payment on) sale of businesses				2,473
Acquisition (net of cash and cash equivalents acquired)			(12,500)		0
Purchase price adjustments on acquisition				0
Net cash required by investing activities			(47,839)	(51,470)	(31,575)
Cash provided (required) by financing activities:
Proceeds from long-term debt, net of discounts			0	0
Payment of debt issue costs				0
Repayment of long-term debt			0	0	0
Advances due to (from) affiliates			(155,578)	621,109
Distributions to Dover Corporation, net				(744,258)	(27,124)
Distribution to noncontrolling interest				0	0
Payment of capital lease obligations			(5,493)	(4,518)	(3,690)
Payments related to taxes withheld on stock-based compensation			(1,795)
Net cash required by financing activities			(162,866)	(127,667)	(30,814)
Effect of exchange rate changes on cash and cash equivalents			0	0	0
Net increase (decrease) in cash and cash equivalents			(5,828)	21,770	2,033
Cash and cash equivalents at beginning of period			27,533	5,763	3,730
Cash and cash equivalents at end of period			21,705	27,533	5,763
Subsidiary Non-guarantors
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided (required) by operating activities			(8)	15,720	11,561
Cash provided (required) by investing activities:
Capital expenditures			(2,055)	(2,848)	(1,646)
Proceeds from sale of property, plant and equipment			18	60	114
Proceeds from (payment on) sale of businesses				0
Acquisition (net of cash and cash equivalents acquired)					(8,842)
Purchase price adjustments on acquisition				53
Net cash required by investing activities			(2,037)	(2,735)	(10,374)
Cash provided (required) by financing activities:
Proceeds from long-term debt, net of discounts			0	0
Payment of debt issue costs				0
Repayment of long-term debt			0	0	(599)
Advances due to (from) affiliates			1,608	(20,307)
Distributions to Dover Corporation, net				7,021	(4,001)
Distribution to noncontrolling interest				(2,720)	(1,212)
Payment of capital lease obligations			(62)	0	0
Payments related to taxes withheld on stock-based compensation			(53)
Net cash required by financing activities			1,493	(16,006)	(5,812)
Effect of exchange rate changes on cash and cash equivalents			(162)	(737)	277
Net increase (decrease) in cash and cash equivalents			(714)	(3,758)	(4,348)
Cash and cash equivalents at beginning of period			14,191	17,949	22,297
Cash and cash equivalents at end of period			$ 13,477	$ 14,191	$ 17,949