Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 339,629	$ 387,780
Current assets	942,927	1,217,133
Total assets	6,515,628	6,769,636
Current liabilities	1,070,804	1,190,087
Liabilities	$ 3,699,182	$ 4,704,294
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	49,889,000	49,889,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury stock, shares (in shares)	16,008,000	0
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.004	$ 0.004
Common stock, shares authorized (in shares)	700,000,000	700,000,000
Common stock, shares issued (in shares)	119,575,000	107,450,000
Common stock, shares outstanding (in shares)	119,575,000	107,450,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.004	$ 0.004
Common stock, shares authorized (in shares)	175,000,000	175,000,000
Common stock, shares issued (in shares)	90,831,000	116,865,000
Common stock, shares outstanding (in shares)	90,831,000	116,865,000
Variable Interest Entity, Primary Beneficiary
Cash and cash equivalents	$ 157,003	$ 158,387
Current assets	346,125	483,613
Total assets	948,632	1,196,813
Current liabilities	142,343	207,977
Liabilities	$ 257,199	$ 274,744