Acquisitions (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2016 USD ($) customer shares	Dec. 31, 2016 USD ($) item	Mar. 31, 2017 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 42,208	$ 42,266
Superior Water Company, Inc. [Member]
Business Acquisition [Line Items]
Number of customers | customer	3,900
Total purchase price	$ 16,750
Shares issued for acquisition | shares	439,943
Cash Paid	$ 3,905
Acquired property, plant and equipment	25,167
Contributions in aid of construction	16,565
Goodwill	$ 8,622
2016 Acquisitions [Member]
Business Acquisition [Line Items]
Total purchase price		$ 1,721
Number of acquisitions | item		9