Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investment securities held to maturity, fair value	$ 2,838,499	$ 30,996
Total investment securities available for sale, cost	6,911,965	7,052,152
Investments in ME securities, cost	$ 84,837	$ 59,262
Class A Common Stock
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shared authorized	16,000,000	16,000,000
Common stock, shares issued	8,811,220	9,624,310
Common stock, shares outstanding	8,811,220	9,624,310
Class B Common Stock
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shared authorized	2,000,000	2,000,000
Common stock, shares issued	1,005,185	1,005,185
Common stock, shares outstanding	1,005,185	1,005,185
Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	345,000	0
Preferred stock, shares outstanding	345,000	0