Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts receivable, allowance for doubtful accounts	$ 17,970	$ 11,944
Common stock, number of shares authorized	1,000,000,000	1,000,000,000
Common stock, number of shares issued	0	0
Common stock, number of shares outstanding	0	0
Class A Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, number of shares authorized	1,000,000,000	1,000,000,000
Common stock, number of shares issued	117,500,405	110,291,709
Common stock, number of shares outstanding	116,468,385	109,259,689
Class B Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, number of shares authorized	120,000,000	120,000,000
Common stock, number of shares issued	15,580,510	15,782,261
Common stock, number of shares outstanding	15,580,510	15,782,261