Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document And Entity Information [Abstract]
Entity Registrant Name	MIDDLESEX WATER CO
Entity Central Index Key	0000066004
Document Type	10-Q
Document Period End Date	Mar. 31, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity a Well-known Seasoned Issuer	No
Entity a Voluntary Filer	No
Entity Reporting Status Current	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		16,141,954
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2015