Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest and Dividend Income, Operating [Abstract]
Interest and fees on loans and leases	$ 185,919	$ 196,521	$ 376,455	$ 412,708
Taxable interest and dividends on investments	40,303	50,069	79,917	102,691
Non-taxable interest on investment securities	5,283	5,501	10,616	10,987
Loans held for sale	53	184	144	359
Total interest income	231,558	252,275	467,132	526,745
Interest Expense [Abstract]
Deposits	5,094	18,805	11,533	46,648
Securities sold under agreements to repurchase and other borrowings	860	980	1,495	4,710
Federal Home Loan Bank advances	534	3,748	1,047	10,617
Long-term debt	4,218	4,335	8,441	9,562
Total interest expense	10,706	27,868	22,516	71,537
Net interest income	220,852	224,407	444,616	455,208
Provision for credit losses	(21,500)	40,000	(47,250)	116,000
Net interest income after provision for credit losses	242,352	184,407	491,866	339,208
Noninterest Income [Abstract]
Deposit service fees	41,439	35,839	81,908	78,409
Loan and lease related fees	7,862	6,968	16,175	13,464
Wealth and investment services	10,087	7,102	19,490	15,841
Mortgage banking activities	1,319	4,205	3,961	7,098
Increase in cash surrender value of life insurance policies	3,603	3,624	7,136	7,204
Gain on Sale of Investments	0	0	0	8
Other income	8,392	2,338	20,789	11,430
Total non-interest income	72,702	60,076	149,459	133,454
Noninterest Expense [Abstract]
Compensation and benefits	97,754	99,731	205,354	201,618
Occupancy	14,010	14,245	29,660	28,730
Technology and equipment	27,124	27,468	55,640	55,305
Intangible assets amortization	1,132	962	2,271	1,924
Marketing	3,227	3,286	5,731	6,788
Professional and outside services	21,025	6,158	30,801	11,821
Deposit insurance	3,749	5,015	7,705	9,740
Other expense	19,007	19,719	37,848	39,494
Total non-interest expense	187,028	176,584	375,010	355,420
Income before income tax expense	128,026	67,899	266,315	117,242
Income tax expense	33,991	14,802	64,202	25,946
Net income	94,035	53,097	202,113	91,296
Preferred stock dividends and other	(2,480)	(2,368)	(5,028)	(4,530)
Earnings applicable to common shareholders	$ 91,555	$ 50,729	$ 197,085	$ 86,766
Earnings Per Share, Basic and Diluted [Abstract]
Basic	$ 1.02	$ 0.57	$ 2.19	$ 0.96
Diluted	$ 1.01	$ 0.57	$ 2.19	$ 0.96