Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accounts receivable, allowance for doubtful accounts	$ 1,626	$ 1,512
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Treasury stock, shares	3,599,626	236,171
Common Class A
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	15,698,493	15,342,440
Common Class B
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	33,000,000	33,000,000
Common stock, shares issued	30,027,418	30,027,418
Common stock, shares outstanding	30,027,418	30,027,418