Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt securities available for sale	$ 8,723,242	$ 8,604,250
Debt securities, trading	1,055,106	1,066,108
Mortgage loans - allowance for credit losses	2,573	2,987
Mortgage loans, at fair value	18,738	8,469
Equity securities - cost	$ 16,351	$ 16,549
Class A
STOCKHOLDERS’ EQUITY:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	7,500,000	7,500,000
Common stock, shares issued (in shares)	3,436,020	3,436,020
Common stock, shares outstanding (in shares)	3,436,020	3,436,020
Class B
STOCKHOLDERS’ EQUITY:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000	200,000
Common stock, shares issued (in shares)	200,000	200,000
Common stock, shares outstanding (in shares)	200,000	200,000