Condensed Consolidated Balance Sheets (Unaudited) - Parenthetical - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating lease, right-of-use asset, related party	$ 77,754	$ 0
Other assets, due from related parties	12,526	13,098
Other current liabilities, from related parties	9,159	0
Operating lease liabilities, leases with related parties, excluding current portion	$ 74,641	$ 0
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Senior unsecured notes, amount held by related party	$ 15,000	$ 15,000
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	43,243,000	41,208,000
Common stock, shares outstanding (in shares)	43,243,000	41,208,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares issued (in shares)	102,352,000	104,336,000
Common stock, shares outstanding (in shares)	102,352,000	104,336,000
Related Party
Operating lease, right-of-use asset, related party	$ 42,779	$ 0
Other assets, due from related parties	2,492	1,895
Other current liabilities, from related parties	4,519	0
Operating lease liabilities, leases with related parties, excluding current portion	$ 41,030	$ 0