CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (633,455)	$ 19,938
Foreign currency translation adjustments [Abstract]
Foreign currency translation adjustments (1)	[1]	(11,052)	1,090
Pension and other post-retirement benefit plans [Abstract]
Net actuarial loss arising during period		0	(323)
Reclassification adjustment for net actuarial loss included in net income		99	67
Reclassification adjustment for settlement losses included in net income		0	355
Total pension and other post-retirement benefit plans (2)	[2]	99	99
Other comprehensive income (loss)		(10,953)	1,189
Comprehensive income (loss)		(644,408)	21,127
Comprehensive income attributable to noncontrolling interest		273	282
Comprehensive income (loss) attributable to Apergy		$ (644,681)	$ 20,845

[1] Net of income tax (expense) benefit of nil for the three months ended March 31, 2020 and 2019.

[2] Net of income tax (expense) benefit of $33 and $38 for the three months ended March 31, 2020 and 2019, respectively.