Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 17, 2016	Jun. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	LDL
Entity Registrant Name	LYDALL INC /DE/
Entity Central Index Key	0000060977
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		17,115,378
Entity Public Float			$ 482,323,396