Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Allowance for uncollectible accounts	$ 350	$ 4,735
Shareholders’ equity:
Common stock, shares authorized	240,000,000	240,000,000
Common stock, shares issued	106,289,000	105,586,000