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	$ 95,828	$ 83,394	$ 275,744	$ 238,261
Investment securities:
Taxable	20,213	21,003	62,121	60,998
Tax-exempt	1,981	2,409	6,263	7,357
Other interest income	352	139	719	484
Total interest income	118,374	106,945	344,847	307,100
Interest expense:
Savings deposits	3,353	1,599	8,872	4,241
Time deposits	3,493	2,426	9,172	7,203
Securities sold under repurchase agreements	468	1,177	1,839	5,391
Other borrowings	4,358	3,396	13,426	7,234
Junior subordinated deferrable interest debentures	1,828	1,395	5,119	3,967
Total interest expense	13,500	9,993	38,428	28,036
Net interest income	104,874	96,952	306,419	279,064
Provision for probable loan losses	4,280	6,591	3,212	9,096
Net interest income after provision for probable loan losses	100,594	90,361	303,207	269,968
Non-interest income:
Investment securities transactions, net	(141)		(141)	(1,612)
Other investments, net	5,625	4,938	16,192	12,036
Other income	3,643	2,774	13,425	8,569
Total non-interest income	42,503	41,366	123,781	113,044
Non-interest expense:
Employee compensation and benefits	35,360	33,787	104,670	99,256
Occupancy	6,839	6,416	20,077	18,824
Depreciation of bank premises and equipment	6,460	6,407	19,097	18,936
Professional fees	4,063	3,577	10,010	11,143
Deposit insurance assessments	928	1,007	2,902	2,310
Net expense, other real estate owned	911	(407)	3,289	989
Amortization of identified intangible assets				25
Advertising	2,020	2,064	5,667	6,448
Early termination fee - securities sold under repurchase agreements				5,765
Software and software maintenance	4,481	4,302	12,943	12,155
Other	17,005	14,558	48,922	45,199
Total non-interest expense	78,067	71,711	227,577	221,050
Income before income taxes	65,030	60,016	199,411	161,962
Provision for income taxes	13,935	20,388	42,009	49,761
Net income	$ 51,095	$ 39,628	$ 157,402	$ 112,201
Basic earnings per common share:
Weighted average number of shares outstanding (in shares)	66,136,091	66,060,829	66,114,482	66,036,501
Net income (in dollars per share)	$ 0.77	$ 0.60	$ 2.38	$ 1.70
Fully diluted earnings per common share:
Weighted average number of shares outstanding (in shares)	66,423,209	66,745,350	66,739,899	66,736,250
Net income (in dollars per share)	$ 0.77	$ 0.59	$ 2.36	$ 1.68
Services charges on deposit accounts
Non-interest income:
Service charges	$ 18,391	$ 18,706	$ 53,658	$ 54,494
Other service charges, commissions and fees, Banking
Non-interest income:
Service charges	13,100	13,095	35,374	34,505
Other service charges, commissions and fees, Non-banking
Non-interest income:
Service charges	$ 1,885	$ 1,853	$ 5,273	$ 5,052