CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Patient accounts receivable, allowance for doubtful accounts	$ 16,526	$ 14,317
Property and equipment, accumulated depreciation	141,793	146,438
Intangible assets, accumulated amortization	$ 25,386	$ 25,374
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	34,786,966	34,569,526
Common Stock, shares outstanding	33,607,282	33,594,572
Treasury Stock at cost, shares	1,179,684	974,954