CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Patient accounts receivable, allowance for doubtful accounts	$ 15,601	$ 20,994
Property and equipment, accumulated depreciation	125,392	113,154
Intangible assets, accumulated amortization	$ 24,926	$ 23,457
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common Stock, par value	$ 0.001	$ 0.001
Common Stock, shares authorized	60,000,000	60,000,000
Common Stock, shares issued	33,278,397	31,876,508
Common Stock, shares outstanding	32,409,474	31,086,619
Treasury Stock at cost, shares	868,923	789,889