Statements of Common Stockholders' Equity (Unaudited) (USD $) In Thousands, except Share data	Common Stock [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2009	$ 73,569	$ 13,353	$ 86,922
Balance (in shares) at Dec. 31, 2009	12,558,724
Net income	0	4,183	4,183
Dividends	0	(3,226)	(3,226)
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans	1,126	0	1,126
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans (in shares)	83,314
Balance at Jun. 30, 2010	74,695	14,310	89,005
Balance (in shares) at Jun. 30, 2010	12,642,038
Balance at Dec. 31, 2010	75,481	15,776	91,257
Balance (in shares) at Dec. 31, 2010	12,692,054		12,692,054
Net income	0	4,597	4,597
Dividends	0	(3,331)	(3,331)
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans	841	0	841
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans (in shares)	51,385
Balance at Jun. 30, 2011	$ 76,322	$ 17,042	$ 93,364
Balance (in shares) at Jun. 30, 2011	12,743,439		12,743,439