Shareholders Equity - Summary of Changes in Shareholders Equity (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Stockholders Equity Note [Line Items]
Beginning Balance	$ 257,813	$ 250,203	$ 249,370	$ 239,529	$ 247,021	$ 238,537	$ 249,370	$ 238,537
Net income	8,044	7,865	1,824	9,054	6,735	5,528	17,733	21,318
Foreign currency translation adjustment	(5,897)	1,100	1,353	(563)	(13,367)	3,832	(3,444)	(10,098)
Recognized net actuarial gain, net of tax provision	108	93	93	116	92	91	294	299
Total comprehensive income	2,255	9,058	3,270	8,607	(6,540)	9,451
Share-based compensation	1,345	985	892	1,404	1,945	781
Purchase of common shares	(751)	(1,456)	(2,294)	(2,313)	(981)	(833)
Issuance of common shares	57	27	141	210	4	94
Common shares issued to rabbi trust	0	0	0	0	0	0
Cash dividends declared per share	(1,002)	(1,004)	(1,176)	(1,032)	(1,920)	(1,009)
Ending Balance	259,717	257,813	250,203	246,405	239,529	247,021	259,717	246,405
Common Shares [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	12,822	12,821	12,662	12,639	12,635	12,593	12,662	12,593
Issuance of common shares	3	1	159	4	4	42
Ending Balance	12,825	12,822	12,821	12,643	12,639	12,635	12,825	12,643
Common Shares Issued to Rabbi Trust [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	(11,066)	(11,038)	(11,008)	(10,988)	(11,849)	(11,834)	(11,008)	(11,834)
Common shares issued to rabbi trust	85	(28)	(30)	(20)	861	(15)
Ending Balance	(10,981)	(11,066)	(11,038)	(11,008)	(10,988)	(11,849)	(10,981)	(11,008)
Deferred Compensation Liability [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	11,066	11,038	11,008	10,988	11,849	11,834	11,008	11,834
Common shares issued to rabbi trust	(85)	28	30	20	(861)	15
Ending Balance	10,981	11,066	11,038	11,008	10,988	11,849	10,981	11,008
Paid In Capital [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	36,200	35,146	34,401	31,657	30,576	29,734	34,401	29,734
Share-based compensation	1,388	1,028	928	1,421	1,994	790
Issuance of common shares	54	26	(18)	206		52
Cash dividends declared per share			(165)		(913)
Ending Balance	37,642	36,200	35,146	33,284	31,657	30,576	37,642	33,284
Retained Earnings [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	341,804	334,947	334,170	321,954	316,275	311,765	334,170	311,765
Net income	7,951	7,904	1,824	9,054	6,735	5,528
Share-based compensation	(43)	(43)	(36)	(17)	(49)	(9)
Cash dividends declared per share	(1,002)	(1,004)	(1,011)	(1,032)	(1,007)	(1,009)
Ending Balance	348,710	341,804	334,947	329,959	321,954	316,275	348,710	329,959
Treasury Stock [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	(76,030)	(74,574)	(72,280)	(69,929)	(68,948)	(68,115)	(72,280)	(68,115)
Purchase of common shares	(751)	(1,456)	(2,294)	(2,313)	(981)	(833)
Ending Balance	(76,781)	(76,030)	(74,574)	(72,242)	(69,929)	(68,948)	(76,781)	(72,242)
Cumulative Translation Adjustment [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	(51,257)	(52,357)	(53,710)	(50,960)	(37,593)	(41,425)	(53,710)	(41,425)
Foreign currency translation adjustment	(5,897)	1,100	1,353	(563)	(13,367)	3,832
Ending Balance	(57,154)	(51,257)	(52,357)	(51,523)	(50,960)	(37,593)	(57,154)	(51,523)
Unrecognized Pension Benefit Cost [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	(5,687)	(5,780)	(5,873)	(5,832)	(5,924)	(6,015)	(5,873)	(6,015)
Recognized net actuarial gain, net of tax provision	108	93	93	116	92	91
Ending Balance	(5,579)	(5,687)	(5,780)	$ (5,716)	$ (5,832)	$ (5,924)	(5,579)	$ (5,716)
Total Preformed Line Products, Company Equity [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	257,852	250,203	249,370				249,370
Net income	7,951	7,904	1,824
Foreign currency translation adjustment	(5,897)	1,100	1,353
Recognized net actuarial gain, net of tax provision	108	93	93
Total comprehensive income	2,162	9,097	3,270
Share-based compensation	1,345	985	892
Purchase of common shares	(751)	(1,456)	(2,294)
Issuance of common shares	57	27	141
Common shares issued to rabbi trust	0	0	0
Cash dividends declared per share	(1,002)	(1,004)	(1,176)
Ending Balance	259,663	257,852	250,203				259,663
Noncontrolling Interests [Member]
Stockholders Equity Note [Line Items]
Beginning Balance	(39)	0	0				0
Net income	93	(39)
Total comprehensive income	93	(39)
Ending Balance	$ 54	$ (39)	$ 0				$ 54