Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Cash and cash equivalents:
Cash and due from banks	$ 588,372	$ 476,653
Federal funds sold and interest-earning deposits with banks	5,414,420	6,018,915
Deposits in other financial institutions (restricted cash)	29,814	347,579
Total cash and cash equivalents	6,032,606	6,843,147
Trading securities, at fair value	74,234	77,689
Investment securities:
Securities held to maturity (fair value of $2,630,495 and $1,778,064)	2,827,769	1,819,901
Securities available for sale, at fair value	5,924,206	5,193,478
Other investments	179,258	160,568
Total investment securities	8,931,233	7,173,947
Loans held for sale	130,376	191,723
Loans:
Total loans	26,556,427	23,928,166
Less allowance for credit losses	(300,396)	(301,807)
Loans, net	26,256,031	23,626,359
Other real estate owned	3,290	2,736
Bank property held for sale	6,417	9,578
Premises and equipment, net	568,332	558,499
Bank owned life insurance ("BOLI")	942,922	783,049
Deferred tax assets	136,078	64,964
Derivatives assets	412,815	414,742
Mortgage servicing rights	83,339	65,620
Core deposit and other intangibles	140,364	128,067
Goodwill	1,924,024	1,581,085
Other assets	559,480	438,827
Total assets	46,201,541	41,960,032
Deposits:
Noninterest-bearing	14,052,332	11,498,840
Interest-bearing	24,723,498	23,555,989
Total deposits	38,775,830	35,054,829
Federal funds purchased	343,819	381,195
Securities sold under agreements to repurchase	426,590	400,044
Corporate and subordinated debentures	405,553	327,066
Reserve for unfunded commitments	30,368	30,510
Derivative liabilities	412,168	410,137
Other liabilities	632,805	553,311
Total liabilities	41,027,133	37,157,092
Shareholders' equity:
Common stock - $2.50 par value; authorized 160,000,000 shares; 75,761,018 and 69,332,297 shares issued and outstanding, respectively	189,403	173,331
Surplus	4,214,897	3,653,098
Retained earnings	1,064,064	997,657
Accumulated other comprehensive loss	(293,956)	(21,146)
Total shareholders' equity	5,174,408	4,802,940
Total liabilities and shareholders' equity	46,201,541	41,960,032
Acquired - non-purchased credit deteriorated loans
Loans:
Total loans	7,633,824	5,890,069
Acquired - purchased credit deteriorated loans
Loans:
Total loans	1,939,033	1,987,322
Non-acquired loans
Loans:
Total loans	$ 16,983,570	$ 16,050,775