Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Stockholders' equity
Preferred stock par value	$ 0.01	$ 0.01
Preferred stock authorized	20,000,000	20,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Class A common stock
Stockholders' equity
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	250,000,000	250,000,000
Common stock, issued	30,227,113	18,935,916
Common stock, outstanding	30,227,061	18,935,916
Class B common stock
Stockholders' equity
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, authorized	75,000,000	75,000,000
Common stock, issued	69,066,445	69,066,445
Common stock, outstanding	57,031,184	62,002,729
Class C common stock
Stockholders' equity
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, authorized	1	1
Common stock, issued	1	1
Common stock, outstanding	1	1