CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ (56,805)	$ (59,689)
Series A convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Series A convertible preferred stock, liquidation preference	$ 71,701	$ 69,702
Series A convertible preferred stock, shares authorized (in shares)	825,000	825,000
Series A convertible preferred stock, shares issued (in shares)	635,822	635,822
Series A convertible preferred stock, shares outstanding (in shares)	635,822	635,822
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	4,175,000	4,175,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares, issued (in shares)	71,441,664	71,421,664
Common stock, shares, outstanding (in shares)	68,780,241	68,767,613
Treasury stock, shares (in shares)	2,661,423	2,654,051