Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income
Interest and fees on loans	$ 1,157,249	$ 1,228,480	$ 1,044,502
Mortgage loans held-for-sale	20,077	11,992	15,738
Interest-bearing deposits with banks	8,553	29,803	17,090
Federal funds sold and securities purchased under resale agreements	102	700	1
Investment securities	99,634	108,046	87,382
Trading account securities	37	39	43
Federal Home Loan Bank and Federal Reserve Bank stock	6,891	5,416	5,331
Brokerage customer receivables	477	666	723
Total interest income	1,293,020	1,385,142	1,170,810
Interest expense
Interest on deposits	189,178	278,892	166,553
Interest on Federal Home Loan Bank advances	18,193	9,878	12,412
Interest on other borrowings	12,773	13,897	8,599
Interest on subordinated notes	21,961	15,555	7,121
Interest on junior subordinated debentures	11,008	12,001	11,222
Total interest expense	253,113	330,223	205,907
Net interest income	1,039,907	1,054,919	964,903
Provision for credit losses	214,220	53,864	34,832
Net interest income after provision for credit losses	825,687	1,001,055	930,071
Non-interest income
Revenue from contracts with customers	170,130	161,465	152,513
Mortgage banking	346,013	154,293	136,990
(Losses) gains on investment securities, net	(1,926)	3,525	(2,898)
Fees from covered call options	2,292	3,670	3,519
Trading (losses) gains, net	(1,004)	(158)	11
Operating lease income, net	47,604	47,041	38,451
Other	65,851	62,617	52,710
Total non-interest income	604,189	407,172	356,150
Non-interest expense
Salaries and employee benefits	626,076	546,420	480,077
Equipment	68,496	52,328	42,949
Operating lease equipment depreciation	37,915	35,760	29,305
Occupancy, net	69,957	64,289	57,814
Data processing	30,196	27,820	35,027
Advertising and marketing	36,296	48,595	41,140
Professional fees	27,426	27,471	32,306
Amortization of other intangible assets	11,018	11,844	4,571
FDIC insurance	25,004	9,199	17,209
OREO expense, net	(921)	3,628	6,120
Other	108,632	100,772	79,570
Total non-interest expense	1,040,095	928,126	826,088
Income before taxes	389,781	480,101	460,133
Income tax expense	96,791	124,404	116,967
Net income	292,990	355,697	343,166
Preferred stock dividends	21,377	8,200	8,200
Net income applicable to common shares	$ 271,613	$ 347,497	$ 334,966
Net income per common share-Basic (usd per share)	$ 4.72	$ 6.11	$ 5.95
Net income per common share-Diluted (usd per share)	4.68	6.03	5.86
Cash dividends declared per common share (usd per share)	$ 1.12	$ 1.00	$ 0.76
Weighted average common shares outstanding (in shares)	57,523	56,857	56,300
Dilutive potential common shares (in shares)	496	762	908
Average common shares and dilutive common shares (in shares)	58,019	57,619	57,208
Wealth management
Non-interest income
Revenue from contracts with customers	$ 100,336	$ 97,114	$ 90,963
Service charges on deposit accounts
Non-interest income
Revenue from contracts with customers	$ 45,023	$ 39,070	$ 36,404