Short-Term Borrowings (Tables)

3 Months Ended

Mar. 31, 2012

Line of Credit Facility [Line Items]

Schedule Of Balances Outstanding And Interest Rates Of Borrowings

	March 31, 2012			December 31, 2011
Balance outstanding at end of period	$	37,000		$	61,000
Letters of credit outstanding at end of period	$	20,090		$	29,030
Average interest rate at end of period		3.25	%		1.12	%

Ecova [Member]

Line of Credit Facility [Line Items]

Schedule Of Balances Outstanding And Interest Rates Of Borrowings

	March 31, 2012			December 31, 2011
Balance outstanding at end of period	$	60,000		$	35,000
Average interest rate at end of period		2.25	%		2.38	%