CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Accounts receivable, allowance for doubtful accounts	$ 7,959	$ 6,917
Stockholders' Equity
Preferred Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, authorized (in shares)	5,000,000	5,000,000
Preferred Stock, issued (in shares)	0	0
Preferred Stock, outstanding (in shares)	0	0
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, authorized (in shares)	50,000,000	50,000,000
Common Stock, issued (in shares)	20,722,939	21,043,947
Common Stock, outstanding (in shares)	20,722,939	21,043,947