Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Loans and leases	$ 1,047,969	$ 952,771	$ 924,294
Investment securities	111,619	98,202	90,557
Deposits in financial institutions	2,082	1,543	1,061
Total interest income	1,161,670	1,052,516	1,015,912
Interest expense:
Deposits	80,140	45,694	31,512
Borrowings	11,985	3,638	2,259
Subordinated debentures	28,631	23,613	20,850
Total interest expense	120,756	72,945	54,621
Net interest income	1,040,914	979,571	961,291
Provision for credit losses	45,000	57,752	65,729
Net interest income after provision for credit losses	995,914	921,819	895,562
Noninterest income:
Service charges on deposit accounts	16,509	15,307	14,534
Other commissions and fees	45,543	41,422	47,126
Leased equipment income	37,881	37,700	33,919
Gain on sale of loans and leases	4,675	6,197	909
Gain (loss) on sale of securities	8,176	(541)	9,485
FDIC loss sharing expense, net	0	0	(8,917)
Other income	35,851	28,488	15,419
Total noninterest income	148,635	128,573	112,475
Noninterest expense:
Compensation	282,568	266,567	251,913
Occupancy	53,223	48,863	48,911
Data processing	27,225	26,575	24,356
Other professional services	21,952	17,353	16,478
Insurance and assessments	20,705	19,733	18,364
Intangible asset amortization	22,506	14,240	16,517
Leased equipment depreciation	21,371	20,767	20,899
Foreclosed assets (income) expense, net	(751)	1,702	1,881
Acquisition, integration and reorganization costs	1,770	19,735	200
Loan expense	10,569	13,832	9,371
Other expense	50,094	46,294	41,211
Total noninterest expense	511,232	495,661	450,101
Earnings before income taxes	633,317	554,731	557,936
Income tax expense	(167,978)	(196,913)	(205,770)
Net earnings	$ 465,339	$ 357,818	$ 352,166
Earnings Per Share, Basic (usd per share)	$ 3.72	$ 2.91	$ 2.90
Diluted income per share (usd per share)	3.72	2.91	2.90
Dividends declared per share (usd per share)	$ 2.30	$ 2.00	$ 2.00