Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets [Abstract]
Cash and due from banks	$ 735,836	$ 741,749
Interest-bearing cash and cash equivalents	522,985	401,675
Trading securities	1,623,921	1,956,923
Investment securities	293,418	355,187
Available for sale securities	11,269,643	8,857,120
Fair value option securities	1,098,577	283,235
Restricted equity securities	460,552	344,447
Residential mortgage loans held for sale	182,271	149,221
Loans	21,750,987	21,656,730
Allowance for loan losses	(210,759)	(207,457)
Loans, net of allowance	21,540,228	21,449,273
Premises and equipment, net	535,519	330,033
Receivables	231,811	204,960
Goodwill	1,048,091	1,049,263
Intangible assets, net	125,271	134,849
Mortgage servicing rights	201,886	259,254
Real estate and other repossessed assets, net of allowance	20,359	17,487
Derivative contracts	323,375	320,929
Cash surrender value of bank-owned life insurance	389,879	381,608
Receivable on unsettled securities sales	1,020,404	336,400
Other assets	547,995	446,891
Total assets	42,172,021	38,020,504
Deposits [Abstract]
Noninterest-bearing demand deposits	9,461,291	10,414,592
Interest-bearing Deposit Liabilities [Abstract]
Transaction	15,391,752	12,206,576
Savings	550,276	529,215
Time	2,217,849	2,113,380
Total deposits	27,621,168	25,263,763
Funds purchased and repurchase agreements	3,818,350	1,018,411
Other borrowings	4,527,055	6,124,390
Subordinated debentures	275,923	275,913
Accrued interest, taxes and expense	259,701	192,826
Derivative contracts	251,128	362,306
Due on unsettled securities purchases	182,547	156,370
Other liabilities	372,230	183,480
Total liabilities	37,308,102	33,577,459
Shareholders' equity: [Abstract]
Common stock	5	5
Capital surplus	1,350,995	1,334,030
Retained earnings	3,729,778	3,369,654
Treasury stock	(329,906)	(198,995)
Accumulated other comprehensive income (loss)	104,923	(72,585)
Total shareholders’ equity	4,855,795	4,432,109
Non-controlling interests	8,124	10,936
Total equity	4,863,919	4,443,045
Total liabilities and equity	$ 42,172,021	$ 38,020,504