CONSOLIDATED BALANCE SHEETS [Parenthetical] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts receivable (in dollars)	$ 6,991	$ 6,899
Convertible Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible Preferred stock, shares authorized	1,000,000	1,000,000
Convertible Preferred stock, shares outstanding	0	0
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	30,000,000	30,000,000
Common stock, shares issued	1,693,099	2,103,907
Common stock, shares outstanding	1,693,099	2,103,907
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	2,861,843	2,861,843
Common stock, shares outstanding	2,861,843	2,861,843
Common Class C [Member]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	2,928,906	2,928,906
Common stock, shares outstanding	2,928,906	2,928,906
Common Class D [Member]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	41,159,474	42,096,641
Common stock, shares outstanding	41,159,474	42,096,641