Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
HTM debt securities	$ 1,148,804,000	$ 437,193,000
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock authorized (in shares)	10,000,000	10,000,000
Preferred stock liquidation preference (in dollars per share)	$ 25,000	$ 25,000
Preferred stock issued (in shares)	4,000	4,000
Preferred stock outstanding (in shares)	4,000	4,000
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock authorized (in shares)	200,000,000	150,000,000
Common stock issued (in shares)	89,349,826	86,675,279
Common stock outstanding (in shares)	89,349,826	86,675,279
Common stock issuable (in shares)	595,705	600,834