Summary Of Significant Accounting Policies (Materials And Supplies Fuel Stock And Natural Gas Stored) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Materials and supplies	$ 31,016	$ 28,747
Fuel stock	4,945	3,170
Natural gas stored	13,476	13,029
Total	$ 49,437	$ 44,946