Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Cash and cash equivalents:
Cash and due from banks	$ 514,917	$ 548,387
Federal funds sold and interest-earning deposits with banks	587,626	580,491
Deposits in other financial institutions (restricted cash)	226,594	183,685
Total cash and cash equivalents	1,329,137	1,312,563
Trading securities, at fair value	114,154	31,263
Investment securities:
Securities held to maturity (fair value of $2,012,400 and $2,250,168)	2,533,713	2,683,241
Securities available for sale, at fair value	4,623,618	5,326,822
Other investments	187,152	179,717
Total investment securities	7,344,483	8,189,780
Loans held for sale	27,443	28,968
Loans:
Total loans	32,016,672	30,177,862
Less allowance for credit losses	(447,956)	(356,444)
Loans, net	31,568,716	29,821,418
Other real estate owned	434	1,023
Bank property held for sale	15,251	17,754
Premises and equipment, net	516,583	520,635
Bank owned life insurance ("BOLI")	984,881	964,708
Deferred tax assets	150,422	177,801
Derivatives assets	212,345	211,016
Mortgage servicing rights	89,476	86,610
Core deposit and other intangibles	95,094	116,450
Goodwill	1,923,106	1,923,106
Other assets	617,603	515,601
Total assets	44,989,128	43,918,696
Deposits:
Noninterest-bearing	11,158,431	13,168,656
Interest-bearing	25,776,767	23,181,967
Total deposits	36,935,198	36,350,623
Federal funds purchased	253,486	213,597
Securities sold under agreements to repurchase	259,818	342,820
Corporate and subordinated debentures	391,997	392,275
Reserve for unfunded commitments	62,347	67,215
Derivative liabilities	1,251,878	1,034,143
Other liabilities	603,417	443,096
Total liabilities	39,758,141	38,843,769
Shareholders' equity:
Common stock - $2.50 par value; authorized 160,000,000 shares; 76,017,366 and 75,704,563 shares issued and outstanding, respectively	190,043	189,261
Surplus	4,238,753	4,215,712
Retained earnings	1,618,080	1,347,042
Accumulated other comprehensive loss	(815,889)	(677,088)
Total shareholders' equity	5,230,987	5,074,927
Total liabilities and shareholders' equity	44,989,128	43,918,696
Acquired - non-purchased credit deteriorated loans
Loans:
Total loans	5,064,254	5,943,092
Acquired - purchased credit deteriorated loans
Loans:
Total loans	1,171,543	1,429,731
Non-acquired loans
Loans:
Total loans	$ 25,780,875	$ 22,805,039