CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance (in dollars)	$ 830	$ 1,158
Accounts receivable, allowance for appeals (in dollars)	$ 6,985	$ 3,003
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	92,374,539	90,575,837
Common stock, shares outstanding	86,949,692	85,587,299
Treasury stock, shares	5,424,847	4,988,538