CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
CURRENT ASSETS:
Accounts receivable, allowance	$ 20,642	$ 24,960
PROPERTY, EQUIPMENT AND FACILITIES, net of accumulated depreciation and amortization	119,842	111,164
OTHER ASSETS:
Noncurrent receivables, allowance	$ 1,777	$ 2,033
STOCKHOLDERS' EQUITY:
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	28,538,640	28,109,987
Common stock, shares outstanding (in shares)	28,538,640	28,109,987
Treasury stock, shares (in shares)	5,910,541	5,910,541