Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 288,363	$ 289,051
Less accumulated depreciation	(76,678)	(75,592)
Net property, plant and equipment	211,685	213,459
Mains/lines/sewers
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 119,368	117,381
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	47 years
Plant
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 77,754	72,863
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	25 years
Equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 31,223	29,904
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	10 years
Meters
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 13,088	12,693
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	12 years
Furniture, fixture and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 371	368
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	8 years
Computer and office equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 603	720
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	5 years
Software
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 241	242
Average Depreciation Life (in years)
Property plant and equipment, average depreciation life	3 years
Land and land rights
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 891	861
Other
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	428	428
Construction work-in-process
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 44,396	$ 53,591