Consolidated Statements Of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Interest income
Interest and fees on loans	$ 294,746	$ 309,161	$ 596,585	$ 606,148
Mortgage loans held-for-sale	4,764	3,104	7,929	5,313
Interest bearing deposits with banks	1,310	5,206	6,078	10,506
Federal funds sold and securities purchased under resale agreements	16	0	102	0
Investment securities	27,105	27,721	59,572	55,677
Trading account securities	13	5	20	13
Federal Home Loan Bank and Federal Reserve Bank stock	1,765	1,439	3,342	2,794
Brokerage customer receivables	97	178	255	333
Total interest income	329,816	346,814	673,883	680,784
Interest expense
Interest on deposits	50,057	67,024	117,492	128,000
Interest on Federal Home Loan Bank advances	4,934	4,193	8,294	6,643
Interest on other borrowings	3,436	3,525	6,982	7,158
Interest on subordinated notes	5,506	2,806	10,978	4,581
Interest on junior subordinated debentures	2,752	3,064	5,563	6,214
Total interest expense	66,685	80,612	149,309	152,596
Net interest income	263,131	266,202	524,574	528,188
Provision for credit losses	135,053	24,580	188,014	35,204
Net interest income after provision for credit losses	128,078	241,622	336,560	492,984
Non-interest income
Mortgage banking	102,324	37,411	150,650	55,569
Revenue from contracts with customers	38,456	40,065	82,111	79,447
Gains (losses) on investment securities, net	808	864	(3,551)	2,228
Fees from covered call options	0	643	2,292	2,427
Trading losses, net	(634)	(44)	(1,085)	(215)
Operating lease income, net	11,785	11,733	23,769	22,529
Other	14,654	14,135	32,898	31,036
Total non-interest income	161,993	98,158	275,235	179,815
Non-interest expense
Salaries and employee benefits	154,156	133,732	290,918	259,455
Equipment	15,846	12,759	30,680	24,529
Operating lease equipment depreciation	9,292	8,768	18,552	17,087
Occupancy, net	16,893	15,921	34,440	32,166
Data processing	10,406	6,204	18,779	13,729
Advertising and marketing	7,704	12,845	18,566	22,703
Professional fees	7,687	6,228	14,408	11,784
Amortization of other intangible assets	2,820	2,957	5,683	5,899
FDIC insurance	7,081	4,127	11,216	7,703
OREO expense, net	237	1,290	639	(1,922)
Other	27,246	24,776	51,406	47,004
Total non-interest expense	259,368	229,607	494,009	443,981
Income before taxes	30,703	110,173	117,786	228,818
Income tax expense	9,044	28,707	33,315	58,206
Net income	21,659	81,466	84,471	170,612
Preferred stock dividends	2,050	2,050	4,100	4,100
Net income applicable to common shares	$ 19,609	$ 79,416	$ 80,371	$ 166,512
Net income per common share-Basic (usd per share)	$ 0.34	$ 1.40	$ 1.40	$ 2.94
Net income per common share-Diluted (usd per share)	0.34	1.38	1.38	2.91
Cash dividends declared per common share (usd per share)	$ 0.28	$ 0.25	$ 0.56	$ 0.50
Weighted average common shares outstanding (in shares)	57,567	56,662	57,593	56,596
Dilutive potential common shares (in shares)	414	699	481	700
Average common shares and dilutive common shares (in shares)	57,981	57,361	58,074	57,296
Wealth management
Non-interest income
Revenue from contracts with customers	$ 22,636	$ 24,139	$ 48,577	$ 48,116
Service charges on deposit accounts
Non-interest income
Revenue from contracts with customers	$ 10,420	$ 9,277	$ 21,685	$ 18,125