Consolidated Statements Of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest income
Interest and fees on loans	$ 280,479	$ 314,277	$ 877,064	$ 920,425
Mortgage loans held-for-sale	5,791	3,478	13,720	8,791
Interest bearing deposits with banks	1,181	10,326	7,259	20,832
Federal funds sold and securities purchased under resale agreements	0	310	102	310
Investment securities	21,819	24,758	81,391	80,435
Trading account securities	6	20	26	33
Federal Home Loan Bank and Federal Reserve Bank stock	1,774	1,294	5,116	4,088
Brokerage customer receivables	106	164	361	497
Total interest income	311,156	354,627	985,039	1,035,411
Interest expense
Interest on deposits	39,084	76,168	156,576	204,168
Interest on Federal Home Loan Bank advances	4,947	1,774	13,241	8,417
Interest on other borrowings	3,012	3,466	9,994	10,624
Interest on subordinated notes	5,474	5,470	16,452	10,051
Interest on junior subordinated debentures	2,703	2,897	8,266	9,111
Total interest expense	55,220	89,775	204,529	242,371
Net interest income	255,936	264,852	780,510	793,040
Provision for credit losses	25,026	10,834	213,040	46,038
Net interest income after provision for credit losses	230,910	254,018	567,470	747,002
Non-interest income
Mortgage banking	108,544	50,864	259,194	106,433
Revenue from contracts with customers	42,797	40,834	124,908	120,281
Gains (losses) on investment securities, net	411	710	(3,140)	2,938
Fees from covered call options	0	0	2,292	2,427
Trading gains (losses), net	183	11	(902)	(204)
Operating lease income, net	11,717	12,025	35,486	34,554
Other	13,284	17,556	46,182	48,592
Total non-interest income	170,593	115,137	445,828	294,952
Non-interest expense
Salaries and employee benefits	164,042	141,024	454,960	400,479
Equipment	17,251	13,314	47,931	37,843
Operating lease equipment depreciation	9,425	8,907	27,977	25,994
Occupancy, net	15,830	14,991	50,270	47,157
Data processing	5,689	6,522	24,468	20,251
Advertising and marketing	7,880	13,375	26,446	36,078
Professional fees	6,488	8,037	20,896	19,821
Amortization of other intangible assets	2,701	2,928	8,384	8,827
FDIC insurance	6,772	148	17,988	7,851
OREO expense, net	(168)	1,170	(807)	3,092
Other	28,309	24,138	79,715	71,142
Total non-interest expense	264,219	234,554	758,228	678,535
Income before taxes	137,284	134,601	255,070	363,419
Income tax expense	29,969	35,480	63,284	93,686
Net income	107,315	99,121	191,786	269,733
Preferred stock dividends	10,286	2,050	14,386	6,150
Net income applicable to common shares	$ 97,029	$ 97,071	$ 177,400	$ 263,583
Net income per common share-Basic (usd per share)	$ 1.68	$ 1.71	$ 3.08	$ 4.65
Net income per common share-Diluted (usd per share)	1.67	1.69	3.06	4.60
Cash dividends declared per common share (usd per share)	$ 0.28	$ 0.25	$ 0.84	$ 0.75
Weighted average common shares outstanding (in shares)	57,597	56,690	57,595	56,627
Dilutive potential common shares (in shares)	449	773	469	724
Average common shares and dilutive common shares (in shares)	58,046	57,463	58,064	57,351
Wealth management
Non-interest income
Revenue from contracts with customers	$ 24,957	$ 23,999	$ 73,534	$ 72,115
Service charges on deposit accounts
Non-interest income
Revenue from contracts with customers	$ 11,497	$ 9,972	$ 33,182	$ 28,097