Statements of Common Stockholders' Equity (Unaudited) (USD $) In Thousands, except Share data	Common Stock [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2010	$ 75,481	$ 15,776	$ 91,257
Balance (in shares) at Dec. 31, 2010	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
Balance at Dec. 31, 2011	77,113	18,152	95,265
Balance (in shares) at Dec. 31, 2011	12,791,671		12,791,671
Net income	0	4,145	4,145
Dividends	0	(3,425)	(3,425)
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans	1,092	0	1,092
Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans (in shares)	63,800
Balance at Jun. 30, 2012	$ 78,205	$ 18,872	$ 97,077
Balance (in shares) at Jun. 30, 2012	12,855,471		12,855,471