Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Investments measured at fair value	$ 342,266	$ 329,435
Assets sold under agreements to repurchase at fair value	$ 84,200	$ 98,085
Class A Shares
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	21,946,639	21,284,945
Common stock, shares outstanding	21,946,639	21,284,945
Class B Shares
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	32,845,414	29,208,952
Common stock, shares outstanding	32,845,414	29,208,952