Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Income:
Interest and fees on loans and leases	$ 924,693,000	$ 842,449,000	$ 708,566,000
Taxable interest and dividends on securities	207,294,000	191,493,000	181,131,000
Non-taxable interest on securities	21,869,000	20,597,000	22,874,000
Loans held for sale	727,000	628,000	1,034,000
Interest income	1,154,583,000	1,055,167,000	913,605,000
Interest Expense:
Deposits	129,577,000	90,407,000	62,253,000
Securities sold under agreements to repurchase and other borrowings	17,953,000	13,491,000	14,365,000
Federal Home Loan Bank advances	31,399,000	33,461,000	30,320,000
Long-term debt	20,527,000	11,127,000	10,380,000
Interest expense	199,456,000	148,486,000	117,318,000
Net interest income	955,127,000	906,681,000	796,287,000
Provision for loan and lease losses	37,800,000	42,000,000	40,900,000
Net interest income (loss) after provision for loan and lease losses	917,327,000	864,681,000	755,387,000
Non-interest Income:
Deposit service fees	168,022,000	162,183,000	151,137,000
Loan and lease related fees	31,327,000	32,025,000	26,448,000
Wealth and investment services	32,932,000	32,843,000	31,055,000
Mortgage banking activities	6,115,000	4,424,000	9,937,000
Increase in cash surrender value of life insurance policies	14,612,000	14,614,000	14,627,000
Gain on the sale of investment securities, net	29,000	0	0
Impairment loss on securities recognized in earnings	0	0	(126,000)
Other income	32,278,000	36,479,000	26,400,000
Total non-interest income	285,315,000	282,568,000	259,478,000
Non-interest Expense:
Compensation and benefits	395,402,000	381,496,000	356,505,000
Occupancy	57,181,000	59,463,000	60,490,000
Technology and equipment	105,283,000	97,877,000	89,464,000
Intangible assets amortization	3,847,000	3,847,000	4,062,000
Marketing	16,286,000	16,838,000	17,421,000
Professional and outside services	21,380,000	20,300,000	16,858,000
Deposit insurance	17,954,000	34,749,000	25,649,000
Other expense	98,617,000	91,046,000	90,626,000
Total non-interest expense	715,950,000	705,616,000	661,075,000
Income before income tax expense	486,692,000	441,633,000	353,790,000
Income tax expense	103,969,000	81,215,000	98,351,000
Net income	382,723,000	360,418,000	255,439,000
Preferred stock dividends and other	(9,738,000)	(8,715,000)	(8,608,000)
Earnings applicable to common shareholders	$ 372,985,000	$ 351,703,000	$ 246,831,000
Earnings per common share:
Earnings per common share, Basic (in dollars per share)	$ 4.07	$ 3.83	$ 2.68
Earnings per common share, Diluted (in dollars per share)	$ 4.06	$ 3.81	$ 2.67