Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Current assets:
Allowance for uncollectible accounts	$ 4,130	$ 4,527
Shareholders' equity:
Common stock, par value
Common stock, shares authorized	240,000	240,000
Common stock, shares issued	105,965	105,592