Supplemental Cash Flow Information - Supplemental Cash Flow Information and Non-cash Investing and Financing Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental cash flow information
Cash paid during the period for interest	$ 25,850	$ 29,981	$ 26,403
Cash (received) paid during the period for taxes	(31)	75	36
Non-cash investing and financing activities
Non-cash right of way additions to electric plant		337	1,275
Change in accrued additions to electric plant	6,942	20,633	8,876
Allowance for funds used during construction - debt	1,767	1,635	12,579
Net non-cash equity issuances related to the Merger and Reorganization	97,193
Net non-cash noncontrolling equity issuances related to the Merger and Reorganization	119,607
Non-cash members' contributions			369
Non-cash noncontrolling interests contributions			119
Non-cash noncontrolling interests equity issuance	755	4,648	$ 32,052
Dividends and distributions payable	$ 13,634	$ 14,130