Significant Accounting Policies and Responsibility for Financial Statements Significant Accounting Policies and Responsibility for Financial Statements (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended				1 Months Ended
	Jul. 31, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Texas-New Mexico Power Company [Member]	Jun. 30, 2013 Texas-New Mexico Power Company [Member]	Jul. 31, 2014 Subsequent Event [Member]
Dividends on Common Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.165	$ 0.185	$ 0.165	$ 0.370	$ 0.330			$ 0.185
Dividends, Common Stock, Cash				$ 14,736		$ 6,803	$ 3,700