Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Available-for-sale, allowance for credit loss	$ 0	$ 112
Debt securities, held-to-maturity, allowance for credit loss	0	0
Investment securities held-to-maturity	63,304	0
Loans held for sale, fair value	$ 1,435,805	$ 1,001,807
Preferred stock, stated value (in dollars per share)	$ 1,000	$ 1,000
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares Issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	72,015,926	71,753,705
Treasury stock, shares (in shares)	2,380,491	2,212,224