Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Allowance for uncollectible accounts	$ 1,371	$ 2,234
Shareholders' equity:
Common stock, par value
Common stock, shares authorized	240,000	240,000
Common stock, shares issued	105,532	105,640