Condensed Consolidating Financial Information - Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jul. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 35,290		$ 41,832	$ 23,712	$ 26,027
Receivables	219,874		251,436
Inventories, net	211,342		219,421
Prepaid expenses and other current assets	26,934		18,534
Total current assets	493,440		531,223
Property, plant and equipment, net	248,181		244,328
Goodwill	911,113	$ 5,510	904,985	910,088
Advances due from affiliates	0		0
Investment in subsidiaries	0		0
Intangible assets, net	238,707		283,688
Other non-current assets	31,384		8,892
Total assets	1,922,825		1,973,116
Liabilities and Equity
Accounts payable	120,291		140,125
Accrued compensation and employee benefits	38,470		40,546
Current portion of finance lease liabilities	4,845
Current portion of finance lease liabilities			4,320
Accrued expenses and other current liabilities	36,075		28,761
Total current liabilities	199,681		213,752
Advances due to affiliates	0		0
Long-term debt	559,821		663,207
Deferred income taxes	84,060		99,772
Other long-term liabilities	43,049		20,402
Total liabilities	886,611		997,133
Stockholders’ equity:
Stockholders’ capital	1,076,997		1,016,431
Accumulated other comprehensive loss	(44,037)		(42,906)
Total stockholders’ equity	1,032,960		973,525
Noncontrolling interest	3,254		2,458
Total equity	1,036,214		975,983	1,635,509	1,548,504
Total liabilities and equity	1,922,825		1,973,116
Adjustments and eliminations
Assets
Cash and cash equivalents	0		0	0	0
Receivables	(9,799)		(17,044)
Inventories, net	(1,269)		(1,632)
Prepaid expenses and other current assets	0		(24,542)
Total current assets	(11,068)		(43,218)
Property, plant and equipment, net	0		0
Goodwill	0		0
Advances due from affiliates	(603,967)		(697,876)
Investment in subsidiaries	(2,331,101)		(2,231,492)
Intangible assets, net	0		0
Other non-current assets	0		0
Total assets	(2,946,136)		(2,972,586)
Liabilities and Equity
Accounts payable	(9,799)		(17,044)
Accrued compensation and employee benefits	0		0
Current portion of finance lease liabilities	0
Current portion of finance lease liabilities			0
Accrued expenses and other current liabilities	(1,269)		(26,174)
Total current liabilities	(11,068)		(43,218)
Advances due to affiliates	(603,967)		(697,876)
Long-term debt	0		0
Deferred income taxes	0		0
Other long-term liabilities	0		0
Total liabilities	(615,035)		(741,094)
Stockholders’ equity:
Stockholders’ capital	(2,331,101)		(2,231,492)
Accumulated other comprehensive loss	0		0
Total stockholders’ equity	(2,331,101)		(2,231,492)
Noncontrolling interest	0		0
Total equity	(2,331,101)		(2,231,492)
Total liabilities and equity	(2,946,136)		(2,972,586)
Apergy Corporation
Assets
Cash and cash equivalents	108		108	0	0
Receivables	572		1,743
Inventories, net	0		0
Prepaid expenses and other current assets	40		24,583
Total current assets	720		26,434
Property, plant and equipment, net	0		0
Goodwill	0		0
Advances due from affiliates	495,699		600,802
Investment in subsidiaries	1,095,712		1,008,325
Intangible assets, net	0		0
Other non-current assets	3,074		3,996
Total assets	1,595,205		1,639,557
Liabilities and Equity
Accounts payable	60		22
Accrued compensation and employee benefits	0		0
Current portion of finance lease liabilities	0
Current portion of finance lease liabilities			0
Accrued expenses and other current liabilities	3,639		4,929
Total current liabilities	3,699		4,951
Advances due to affiliates	0		0
Long-term debt	555,292		658,623
Deferred income taxes	0		0
Other long-term liabilities	0		0
Total liabilities	558,991		663,574
Stockholders’ equity:
Stockholders’ capital	1,036,214		975,983
Accumulated other comprehensive loss	0		0
Total stockholders’ equity	1,036,214		975,983
Noncontrolling interest	0		0
Total equity	1,036,214		975,983
Total liabilities and equity	1,595,205		1,639,557
Subsidiary Guarantors
Assets
Cash and cash equivalents	21,705		27,533	5,763	3,730
Receivables	190,101		231,718
Inventories, net	181,596		190,117
Prepaid expenses and other current assets	25,571		15,387
Total current assets	418,973		464,755
Property, plant and equipment, net	236,295		231,373
Goodwill	639,281		633,771
Advances due from affiliates	20,582		14,185
Investment in subsidiaries	683,003		682,545
Intangible assets, net	168,711		198,531
Other non-current assets	20,426		2,818
Total assets	2,187,271		2,227,978
Liabilities and Equity
Accounts payable	102,120		123,812
Accrued compensation and employee benefits	31,974		35,278
Current portion of finance lease liabilities	4,745
Current portion of finance lease liabilities			4,320
Accrued expenses and other current liabilities	28,627		46,458
Total current liabilities	167,466		209,868
Advances due to affiliates	583,386		683,700
Long-term debt	4,388		4,462
Deferred income taxes	68,286		79,344
Other long-term liabilities	36,610		19,441
Total liabilities	860,136		996,815
Stockholders’ equity:
Stockholders’ capital	1,336,012		1,238,517
Accumulated other comprehensive loss	(8,877)		(7,354)
Total stockholders’ equity	1,327,135		1,231,163
Noncontrolling interest	0		0
Total equity	1,327,135		1,231,163
Total liabilities and equity	2,187,271		2,227,978
Subsidiary Non-guarantors
Assets
Cash and cash equivalents	13,477		14,191	$ 17,949	$ 22,297
Receivables	39,000		35,019
Inventories, net	31,015		30,936
Prepaid expenses and other current assets	1,323		3,106
Total current assets	84,815		83,252
Property, plant and equipment, net	11,886		12,955
Goodwill	271,832		271,214
Advances due from affiliates	87,686		82,889
Investment in subsidiaries	552,386		540,622
Intangible assets, net	69,996		85,157
Other non-current assets	7,884		2,078
Total assets	1,086,485		1,078,167
Liabilities and Equity
Accounts payable	27,910		33,335
Accrued compensation and employee benefits	6,496		5,268
Current portion of finance lease liabilities	100
Current portion of finance lease liabilities			0
Accrued expenses and other current liabilities	5,078		3,548
Total current liabilities	39,584		42,151
Advances due to affiliates	20,581		14,176
Long-term debt	141		122
Deferred income taxes	15,774		20,428
Other long-term liabilities	6,439		961
Total liabilities	82,519		77,838
Stockholders’ equity:
Stockholders’ capital	1,035,872		1,033,423
Accumulated other comprehensive loss	(35,160)		(35,552)
Total stockholders’ equity	1,000,712		997,871
Noncontrolling interest	3,254		2,458
Total equity	1,003,966		1,000,329
Total liabilities and equity	$ 1,086,485		$ 1,078,167