Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017
Income Tax [Line Items]
Deferred Income Tax Expense	$ (3,209)	$ (3,632)
Internal Revenue Service (IRS) | Latest Tax Year
Income Tax [Line Items]
Tax Year Closed	2011
NEW MEXICO | Latest Tax Year
Income Tax [Line Items]
Tax Year Closed	2011
TEXAS | Earliest Tax Year
Income Tax [Line Items]
Income Tax Examination, Year under Examination	2007
TEXAS | Latest Tax Year
Income Tax [Line Items]
Income Tax Examination, Year under Examination	2011
ARIZONA | Latest Tax Year
Income Tax [Line Items]
Tax Year Closed	2011
Change in Accounting Method Accounted for as Change in Estimate
Income Tax [Line Items]
Regulatory Asset, Amortization Period	15 years
Deferred Income Tax Expense	$ 1,000		$ 5,100