Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Interest income
Interest and fees on loans	$ 285,587	$ 280,479	$ 844,388	$ 877,064
Mortgage loans held-for-sale	7,716	5,791	24,935	13,720
Interest-bearing deposits with banks	2,000	1,181	4,352	7,259
Federal funds sold and securities purchased under resale agreements	0	0	0	102
Investment securities	25,189	21,819	68,076	81,391
Trading account securities	3	6	6	26
Federal Home Loan Bank and Federal Reserve Bank stock	1,777	1,774	5,291	5,116
Brokerage customer receivables	185	106	457	361
Total interest income	322,457	311,156	947,505	985,039
Interest expense
Interest on deposits	19,305	39,084	71,547	156,576
Interest on Federal Home Loan Bank advances	4,931	4,947	14,658	13,241
Interest on other borrowings	2,501	3,012	7,678	9,994
Interest on subordinated notes	5,480	5,474	16,469	16,452
Interest on junior subordinated debentures	2,744	2,703	8,172	8,266
Total interest expense	34,961	55,220	118,524	204,529
Net interest income	287,496	255,936	828,981	780,510
Provision for credit losses	(7,916)	25,026	(68,562)	213,040
Net interest income after provision for credit losses	295,412	230,910	897,543	567,470
Non-interest income
Revenue from contracts with customers	53,219	42,797	151,720	124,908
Mortgage banking	55,794	108,544	219,872	259,194
(Losses) gains on investment securities, net	(2,431)	411	8	(3,140)
Fees from covered call options	1,157	0	2,545	2,292
Trading gains (losses), net	58	183	39	(902)
Operating lease income, net	12,807	11,717	39,487	35,486
Other	23,409	13,284	59,438	46,182
Total non-interest income	136,474	170,593	452,353	445,828
Non-interest expense
Salaries and employee benefits	170,912	164,042	524,538	454,960
Software and equipment	22,029	17,251	63,807	47,931
Operating lease equipment depreciation	10,013	9,425	30,733	27,977
Occupancy, net	18,158	15,830	55,841	50,270
Data processing	7,104	5,689	20,072	24,468
Advertising and marketing	13,443	7,880	33,294	26,446
Professional fees	7,052	6,488	21,943	20,896
Amortization of other intangible assets	1,877	2,701	5,923	8,384
FDIC insurance	6,750	6,772	19,713	17,988
OREO expense, net	(1,531)	(168)	(1,013)	(807)
Other	26,337	28,309	74,294	79,715
Total non-interest expense	282,144	264,219	849,145	758,228
Income before taxes	149,742	137,284	500,751	255,070
Income tax expense	40,605	29,969	133,357	63,284
Net income	109,137	107,315	367,394	191,786
Preferred stock dividends	6,991	10,286	20,973	14,386
Net income applicable to common shares	$ 102,146	$ 97,029	$ 346,421	$ 177,400
Net income per common share-Basic (usd per share)	$ 1.79	$ 1.68	$ 6.08	$ 3.08
Net income per common share-Diluted (usd per share)	1.77	1.67	6.00	3.06
Cash dividends declared per common share (usd per share)	$ 0.31	$ 0.28	$ 0.93	$ 0.84
Weighted average common shares outstanding (in shares)	57,000	57,597	56,985	57,595
Dilutive potential common shares (in shares)	753	449	728	469
Average common shares and dilutive common shares (in shares)	57,753	58,046	57,713	58,064
Wealth management
Non-interest income
Revenue from contracts with customers	$ 31,531	$ 24,957	$ 91,530	$ 73,534
Service charges on deposit accounts
Non-interest income
Revenue from contracts with customers	$ 14,149	$ 11,497	$ 39,434	$ 33,182