Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Maximum Dividends Allowed by Debt Covenants	$ 342,900,000
Investment Portfolio Percentage, Rated AA-, Aa3 and Higher	94.00%		95.00%
Sale and maturity of securities available for sale	$ 11,403,000	$ 7,000,000
Ecova [Member]
Summary Of Significant Accounting Policies [Line Items]
Owners percentage interest	80.20%
Other Intangible Assets [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year
Other Intangible Assets [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Software and Software Development Costs [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Software and Software Development Costs [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Customer Relationships [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years
Customer Relationships [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life	12 years