SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for uncollectible accounts- electric utility | Electric utility
Valuation and qualifying accounts
Balance at beginning of period	$ 1,278	$ 3,822	$ 3,425
Charged to costs and expenses	4,419	(1,296)	4,704
Charged to other accounts	1,857	1,910	8,764
Deductions	5,333	3,158	13,071
Balance at end of period	2,221	1,278	3,822
Allowance for uncollectible interest- bank | Bank
Valuation and qualifying accounts
Balance at beginning of period	4,397	2,947	634
Charged to other accounts	428	1,450	2,313
Balance at end of period	4,825	4,397	2,947
Allowance for losses for loans receivable | Bank
Valuation and qualifying accounts
Balance at beginning of period	40,646	41,679	35,798
Charged to costs and expenses	15,009	20,894	32,000
Charged to other accounts	1,741	2,888	847
Deductions	19,490	24,815	26,966
Balance at end of period	$ 37,906	$ 40,646	$ 41,679