Commitments and Contingent Liabilities (Details Narrative) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Commitments And Contingent Liabilities Details Narrative
Commitment to purchase untreated water	Middlesex has an agreement with the New Jersey Water Supply Authority (NJWSA) for the purchase of untreated water through November 30, 2023, which provides for an average purchase of 27 million gallons a day (mgd). Pricing is set annually by the NJWSA through a public rate making process.
Minimum treated water purchase commitment	Middlesex also has an agreement with a non-affiliated regulated water utility for the purchase of treated water. This agreement, which expires February 27, 2016, provides for the minimum purchase of 3 mgd of treated water with provisions for additional purchases.
Term of water and wastewater system agreement	USA-PA operates the City of Perth Amboy, New Jersey's water and wastewater systems under a 20-year agreement, which expires in 2018. In connection with the agreement with Perth Amboy, USA-PA entered into a 20-year subcontract with a wastewater operating company for the operation and maintenance of the Perth Amboy wastewater collection system.
Budgeted construction cost for construction program, 2014	$ 31,400