Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		6 Months Ended
	Aug. 20, 2021	Jul. 22, 2021	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Business Acquisition Equity Interests Issued Or Issuable [Line Items]
Number of shares authorized to be repurchased			10,300,000		10,300,000
Purchase of treasury stock			$ 30.7	$ 29.0	$ 30.7	$ 41.7
Treasury stock acquired, Shares,			500,000	400,000	500,000	600,000
Treasury Stock Acquired, Average Cost Per Share			$ 60.68	$ 65.85	$ 60.68	$ 64.60
Preferred stock, par value			$ 1	$ 1.00	$ 1	$ 1.00	$ 1
Non-cumulative Perpetual Series D Preferred Stock [Member]
Business Acquisition Equity Interests Issued Or Issuable [Line Items]
Stock Dividend		4.50%
Preferred stock, par value		$ 1.00
Preferred stock liquidation preference per depositary share		25
Preferred stock, liquidation preference per share		$ 25,000
Preferred stock, redemption terms					The Company may redeem the Series D preferred stock at its option, subject to regulatory approval, on or after August 15, 2026.
Underwritten registered public offering		$ 300.0
Non-cumulative Perpetual Series A Preferred Stock [Member]
Business Acquisition Equity Interests Issued Or Issuable [Line Items]
Stock Dividend	6.25%
Preferred stock redemption price per depositary share	$ 25.00
Business Bancshares, Inc. [Member]
Business Acquisition Equity Interests Issued Or Issuable [Line Items]
Issuance of common stock					2,200,000