Significant Accounting Policy Capitalized Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Capitalized Interest Costs, Including Allowance for Funds Used During Construction	$ 1,467	$ 2,509	$ 13,573