Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Pledged securities that can be sold or repledged	$ 85,493	$ 96,128
Investment securities, available for sale, amortized cost	5,783,697	3,849,347
Investment securities, held to maturity, fair value	3,042,709	2,771,290
Equity and other securities, cost	$ 467,884	$ 461,516
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	159,741,898	159,741,898
Common stock issuable, shares	13,864	15,769
Treasury stock, common shares	30,675,930	31,052,845
Series A Series C Series And E Preferred Stock [Member]
Preferred stock, shares issued	350,000	350,000
Preferred stock, shares outstanding	350,000	350,000
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Series F And Series G Preferred Stock [Member]
Preferred stock, shares issued	140,000	140,000
Preferred stock, shares outstanding	140,000	140,000
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000