Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Allowance for uncollectible accounts	$ 4,067	$ 4,067
Shareholders' equity:
Common stock, shares authorized	240,000	240,000
Common stock, shares issued	105,631	105,530