Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest income
Loans and leases	$ 290,922	$ 251,982
Investment securities and dividend income	39,605	35,020
Overnight investments	6,397	5,599
Total interest income	336,924	292,601
Interest expense
Deposits	12,926	3,756
Short-term borrowings	459	404
Federal home loan bank borrowings	1,285	2,384
Subordinated debentures	1,672	1,441
Long-term obligations	110	179
Total interest expense	16,452	8,164
Net interest income	320,472	284,437
Provision (credit) for loan and lease losses	11,750	7,605
Net interest income after provision for loan and lease losses	308,722	276,832
Noninterest income
Marketable equity securities gains, net	11,328	971
Gain on extinguishment of debt	0	25,814
Other	3,919	7,164
Total noninterest income	103,663	122,684
Noninterest expense
Salaries and wages	132,421	129,203
Employee benefits	32,535	32,091
Occupancy expense	27,761	27,954
Equipment expense	26,740	24,974
FDIC insurance expense	2,660	5,733
Collection and foreclosure-related expenses	3,022	4,146
Merger-related expenses	1,719	598
Processing fees paid to third parties	7,089	8,196
Other	33,710	35,168
Total noninterest expense	267,657	268,063
Income before income taxes	144,728	131,453
Income taxes	33,369	31,222
Net income	$ 111,359	$ 100,231
Average shares outstanding (in shares)	11,519,008	12,010,405
Net income per share	$ 9.67	$ 8.35
Cardholder services, net
Noninterest income
Revenue from contract with customers	$ 16,633	$ 14,782
Merchant services, net
Noninterest income
Revenue from contract with customers	5,835	6,177
Service charges on deposit accounts
Noninterest income
Revenue from contract with customers	25,065	26,543
Wealth management services
Noninterest income
Revenue from contract with customers	25,001	23,569
Other service charges and fees
Noninterest income
Revenue from contract with customers	7,422	7,480
Mortgage income
Noninterest income
Revenue from contract with customers	3,658	4,237
Insurance commissions
Noninterest income
Revenue from contract with customers	3,291	3,776
ATM income
Noninterest income
Revenue from contract with customers	$ 1,511	$ 2,171