CONSOLIDATED BALANCE SHEET (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts receivable allowance	$ 11,908	$ 9,263
Property and equipment accumulated depreciation and amortization	27,888	24,368
Accumulated amortization of intangible assets	$ 52,257	$ 36,289
Class A common stock, $0.001 par value; authorized 2,000,000 shares; 63,353 and 62,818 shares issued and outstanding, respectively
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock authorized (shares)	2,000,000,000	2,000,000,000
Common stock issued (shares)	63,353,000	62,818,000
Common stock outstanding (shares)	63,353,000	62,818,000
Class B convertible common stock, $0.001 par value; authorized 1,500,000 shares; 415,885 and 415,186 shares issued and outstanding, respectively
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock authorized (shares)	1,500,000,000	1,500,000,000
Common stock issued (shares)	415,885,000	415,186,000
Common stock outstanding (shares)	415,885,000	415,186,000
Class C common stock, $0.001 par value; authorized 1,500,000 shares; no shares issued and outstanding
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock authorized (shares)	1,500,000,000	1,500,000,000
Common stock issued (shares)	0	0
Common stock outstanding (shares)	0	0