Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest income:
Loans, including fees	$ 189,848	$ 164,133	$ 375,120	$ 315,335
Securities:
Taxable	30,324	21,188	55,003	41,746
Tax-exempt	58,596	57,298	117,739	114,009
Interest-bearing deposits	7,828	13,917	18,467	28,011
Federal funds sold and resell agreements	1,541	1,415	3,129	2,176
Total interest income	288,137	257,951	569,458	501,277
Interest expense:
Deposits	26,844	17,575	54,018	28,213
Federal funds purchased and repurchase agreements	5,220	631	10,236	1,265
Junior subordinated deferrable interest debentures	1,478	1,311	2,976	2,453
Other long-term borrowings	1,164	1,164	2,328	2,328
Total interest expense	34,706	20,681	69,558	34,259
Net interest income	253,431	237,270	499,900	467,018
Provision for loan losses	6,400	8,251	17,403	15,196
Net interest income after provision for loan losses	247,031	229,019	482,497	451,822
Non-interest income:
Trust and investment management fees	30,448	29,121	62,145	58,708
Service charges on deposit accounts	21,798	21,142	42,588	41,985
Insurance commissions and fees	10,118	10,556	28,524	26,536
Interchange and debit card transaction fees	3,868	3,446	7,148	6,604
Other charges, commissions and fees	8,933	9,273	17,995	18,280
Net gain (loss) on securities transactions	169	(60)	169	(79)
Other	7,304	11,588	20,854	24,477
Total non-interest income	82,638	85,066	179,423	176,511
Non-interest expense:
Salaries and wages	90,790	85,204	183,266	171,887
Employee benefits	20,051	17,907	43,577	39,902
Net occupancy	21,133	19,455	40,400	39,195
Technology, furniture and equipment	22,157	20,459	43,821	40,138
Deposit insurance	2,453	4,605	5,261	9,484
Intangible amortization	305	369	630	757
Other	46,320	40,909	88,054	84,156
Total non-interest expense	203,209	188,908	405,009	385,519
Income before income taxes	126,460	125,177	256,911	242,814
Income taxes	14,874	13,836	28,829	24,993
Net income	111,586	111,341	228,082	217,821
Preferred stock dividends	2,015	2,015	4,031	4,031
Net income available to common shareholders	$ 109,571	$ 109,326	$ 224,051	$ 213,790
Earnings per common share:
Basic	$ 1.73	$ 1.70	$ 3.53	$ 3.33
Diluted	$ 1.72	$ 1.68	$ 3.51	$ 3.30