Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income:
Loans, including fees	$ 172,333	$ 138,400	$ 487,668	$ 392,073
Securities:
Taxable	21,339	23,203	63,085	72,032
Tax-exempt	59,200	54,939	173,209	167,321
Interest-bearing deposits	14,445	10,800	42,456	26,712
Federal funds sold and resell agreements	1,399	244	3,575	514
Total interest income	268,716	227,586	769,993	658,652
Interest expense:
Deposits	22,201	5,668	50,414	9,709
Federal funds purchased and repurchase agreements	2,292	523	3,557	849
Junior subordinated deferrable interest debentures	1,394	1,020	3,847	2,890
Other long-term borrowings	1,164	1,164	3,492	2,696
Total interest expense	27,051	8,375	61,310	16,144
Net interest income	241,665	219,211	708,683	642,508
Provision for loan losses	2,650	10,980	17,846	27,358
Net interest income after provision for loan losses	239,015	208,231	690,837	615,150
Non-interest income:
Trust and investment management fees	30,801	27,493	89,509	81,690
Service charges on deposit accounts	21,569	20,967	63,554	62,934
Insurance commissions and fees	11,037	10,892	37,573	34,441
Interchange and debit card transaction fees	3,499	5,884	10,103	17,150
Other charges, commissions and fees	9,580	10,493	27,860	29,983
Net gain (loss) on securities transactions	(34)	(4,867)	(113)	(4,917)
Other	11,205	10,753	35,682	25,114
Total non-interest income	87,657	81,615	264,168	246,395
Non-interest expense:
Salaries and wages	87,547	84,388	259,434	247,895
Employee benefits	18,355	17,730	58,257	57,553
Net occupancy	19,894	19,391	59,089	57,781
Technology, furniture and equipment	21,004	18,743	61,142	54,983
Deposit insurance	4,694	4,862	14,178	15,347
Intangible amortization	336	405	1,093	1,301
Other	41,838	41,304	125,994	127,929
Total non-interest expense	193,668	186,823	579,187	562,789
Income before income taxes	133,004	103,023	375,818	298,756
Income taxes	15,160	9,892	40,153	35,131
Net income	117,844	93,131	335,665	263,625
Preferred stock dividends	2,016	2,016	6,047	6,047
Net income available to common shareholders	$ 115,828	$ 91,115	$ 329,618	$ 257,578
Earnings per common share:
Basic	$ 1.80	$ 1.43	$ 5.13	$ 4.02
Diluted	$ 1.78	$ 1.41	$ 5.08	$ 3.98