Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Allowance for uncollectible accounts	$ 225	$ 225
Capitalization:
Common stock, par value	$ 0.521	$ 0.521
Common stock, shares authorized	36,000,000	36,000,000
Common stock, shares issued	18,670,566	18,592,827
Common stock, shares outstanding	18,670,566	18,592,827