Rate Matters (Details) - PPUC [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Rate Request Filed on May 29, 2013 [Member] | Water [Member]
Rate Matters [Abstract]
Requested increase in annual revenue	$ 7,116
Authorized increase in annual revenue	4,972
Rate Request Filed on May 29, 2013 [Member] | Wastewater [Member]
Rate Matters [Abstract]
Requested increase in annual revenue	28
Authorized increase in annual revenue	28
DSIC [Member]
Rate Matters [Abstract]
Distribution system improvement charge revenue	$ 0	$ 0	$ 283
DSIC [Member] | Maximum [Member]
Rate Matters [Abstract]
Distribution system improvement charge percentage over base rate	5.00%
DSIC [Member] | Minimum [Member]
Rate Matters [Abstract]
Distribution system improvement charge percentage over base rate	0.00%