CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Patient accounts receivable, allowance for uncollectible accounts	$ 23,556	$ 29,036
Property, building and equipment, accumulated depreciation	43,565	35,226
Intangible assets, accumulated amortization	$ 13,041	$ 10,968
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	22,640,046	22,429,041
Treasury stock at cost, shares	4,890,504	4,828,679
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0