CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
ASSETS
Accounts receivable, allowance	$ 13,738	$ 13,787
PROPERTY, EQUIPMENT AND FACILITIES - accumulated depreciation and amortization	156,373	146,795
OTHER ASSETS :
Noncurrent receivables, allowance	$ 988	$ 982
LIABILITIES AND 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)	30,010,170	29,919,761
Common stock, shares outstanding (in shares)	30,010,170	29,919,761
Treasury stock, shares (in shares)	5,910,541	5,910,541