CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 15,114	$ 14,959
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized	50,000,000	50,000,000
Common stock, issued	21,915,468	21,991,718
Common stock, outstanding	21,915,468	21,991,718