Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and cash equivalents:
Cash and due from banks	$ 597,321	$ 363,306
Federal funds sold and interest-earning deposits with banks	5,328,530	3,582,410
Deposits in other financial institutions (restricted cash)	372,472	663,539
Total cash and cash equivalents	6,298,323	4,609,255
Trading securities, at fair value	61,294	10,674
Investment securities:
Securities held to maturity (fair value of $1,607,184 and $957,183)	1,641,485	955,542
Securities available for sale, at fair value	4,631,554	3,330,672
Other investments	160,592	160,443
Total investment securities	6,433,631	4,446,657
Loans held for sale	242,813	290,467
Loans:
Total loans	23,788,949	24,664,134
Less allowance for credit losses	(314,144)	(457,309)
Loans, net	23,474,805	24,206,825
Other real estate owned	3,687	11,914
Bank property held for sale	15,076	36,006
Premises and equipment, net	569,817	579,239
Bank owned life insurance ("BOLI")	778,552	559,368
Deferred tax assets	19,684	110,946
Derivatives assets	489,085	813,899
Mortgage servicing rights	60,922	43,820
Core deposit and other intangibles	136,584	162,592
Goodwill	1,581,085	1,563,942
Other assets	738,350	344,269
Total assets	40,903,708	37,789,873
Deposits:
Noninterest-bearing	11,333,881	9,711,338
Interest-bearing	22,226,677	20,982,544
Total deposits	33,560,558	30,693,882
Federal funds purchased	484,305	384,735
Securities sold under agreements to repurchase	375,431	394,931
Corporate and subordinated debentures	326,807	390,179
Reserve for unfunded commitments	28,289	43,380
Derivative liabilities	485,007	804,832
Other liabilities	850,370	430,054
Total liabilities	36,110,767	33,141,993
Shareholders' equity:
Common stock - $2.50 par value; authorized 160,000,000 shares; 69,918,037 and 70,973,477 shares issued and outstanding, respectively	174,795	177,434
Surplus	3,693,622	3,765,406
Retained earnings	925,044	657,451
Accumulated other comprehensive (loss) income	(520)	47,589
Total shareholders' equity	4,792,941	4,647,880
Total liabilities and shareholders' equity	40,903,708	37,789,873
Acquired - non-purchased credit deteriorated loans
Loans:
Total loans	6,554,647	9,458,869
Acquired - purchased credit deteriorated loans
Loans:
Total loans	2,255,874	2,915,809
Non-acquired loans
Loans:
Total loans	$ 14,978,428	$ 12,289,456