Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts receivable, allowance for credit losses	$ 712	$ 792
Other assets, allowance for credit losses	$ 91	$ 87
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Other current assets, allowance for credit losses	$ 2	$ 0
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	127,546,000	119,009,000
Common stock, shares outstanding (in shares)	127,546,000	119,009,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	113,915,000	121,640,000
Common stock, shares outstanding (in shares)	113,915,000	121,640,000
Class C Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	0	0
Common stock, shares outstanding (in shares)	0	0