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 and leases	$ 303,233	$ 261,086	$ 594,155	$ 513,068
Investment securities and dividend income	40,209	37,179	79,821	72,199
Overnight investments	7,279	5,612	13,669	11,211
Total interest income	350,721	303,877	687,645	596,478
Interest expense
Deposits	19,158	4,521	32,084	8,277
Short-term borrowings	515	373	974	777
Federal Home Loan Bank borrowings	1,586	852	2,871	3,236
Subordinated debentures	1,952	1,653	3,624	3,094
Long-term obligations	162	259	272	438
Total interest expense	23,373	7,658	39,825	15,822
Net interest income	327,348	296,219	647,820	580,656
Provision (credit) for loan and lease losses	5,198	8,438	16,948	16,043
Net interest income after provision for loan and lease losses	322,150	287,781	630,872	564,613
Noninterest income
Debt and Equity Securities, Gain (Loss)	5,719	0	5,719	0
Marketable equity securities gains, net	3,144	4,440	14,472	5,411
Gain on extinguishment of debt	0	0	0	25,814
Other	5,034	6,001	8,953	13,165
Total noninterest income	106,875	100,927	210,538	223,611
Noninterest expense
Salaries and wages	136,526	129,841	268,947	259,044
Employee benefits	30,197	29,715	62,732	61,806
Occupancy expense	26,886	26,100	54,647	54,054
Equipment expense	28,489	25,167	55,229	50,141
FDIC insurance expense	2,757	5,492	5,417	11,225
Collection and foreclosure-related expenses	3,659	3,974	6,681	8,120
Merger-related expenses	4,084	2,412	5,803	3,010
Processing fees paid to third parties	6,641	7,890	13,730	16,086
Other	34,158	35,402	67,868	70,570
Total noninterest expense	273,397	265,993	541,054	534,056
Income before income taxes	155,628	122,715	300,356	254,168
Income taxes	36,269	29,424	69,638	60,646
Net income	$ 119,359	$ 93,291	$ 230,718	$ 193,522
Average shares outstanding (in shares)	11,286,520	12,010,405	11,402,122	12,010,405
Net income per share	$ 10.56	$ 7.77	$ 20.23	$ 16.11
Cardholder services, net
Noninterest income
Revenue from contract with customers	$ 18,479	$ 14,925	$ 35,112	$ 29,707
Merchant services, net
Noninterest income
Revenue from contract with customers	6,455	6,478	12,290	12,655
Service charges on deposit accounts
Noninterest income
Revenue from contract with customers	25,790	25,952	50,855	52,495
Wealth management services
Noninterest income
Revenue from contract with customers	24,573	25,515	49,574	49,084
Other service charges and fees
Noninterest income
Revenue from contract with customers	8,164	7,756	15,586	15,236
Mortgage income
Noninterest income
Revenue from contract with customers	5,038	4,703	8,696	8,940
Insurance commissions
Noninterest income
Revenue from contract with customers	2,854	2,940	6,145	6,716
ATM income
Noninterest income
Revenue from contract with customers	1,625	2,217	$ 3,136	4,388
Retained Earnings
Noninterest expense
Net income	$ 119,359	$ 93,291		$ 193,522