Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest income:
Loans, including fees	$ 92,083	$ 79,466	$ 179,916	$ 154,867
Investment securities:
Taxable	20,694	20,989	41,908	39,995
Tax-exempt	2,087	2,457	4,282	4,948
Other interest income	202	262	367	345
Total interest income	115,066	103,174	226,473	200,155
Interest expense:
Savings deposits	3,291	1,353	5,519	2,642
Time deposits	3,010	2,401	5,679	4,777
Securities sold under repurchase agreements	348	1,146	1,371	4,214
Other borrowings	4,379	2,575	9,068	3,838
Junior subordinated deferrable interest debentures	1,765	1,322	3,291	2,572
Total interest expense	12,793	8,797	24,928	18,043
Net interest income	102,273	94,377	201,545	182,112
Provision for probable loan losses	(2,730)	805	(1,068)	2,505
Net interest income after provision for probable loan losses	105,003	93,572	202,613	179,607
Non-interest income:
Investment securities transactions, net		(2,539)		(1,612)
Other investments, net	5,841	2,830	10,567	7,098
Other income	5,727	2,901	9,782	5,795
Total non-interest income	42,303	33,963	81,278	71,678
Non-interest expense:
Employee compensation and benefits	34,692	32,739	69,310	65,469
Occupancy	7,163	6,417	13,238	12,408
Depreciation of bank premises and equipment	6,364	6,302	12,637	12,529
Professional fees	3,375	3,850	5,947	7,566
Deposit insurance assessments	974	913	1,974	1,303
Net expense, other real estate owned	2,649	482	2,378	1,396
Amortization of identified intangible assets				25
Advertising	1,808	2,116	3,647	4,384
Early termination fee - securities sold under repurchase agreements				5,765
Software and software maintenance	4,390	4,062	8,462	7,853
Other	19,186	16,832	31,917	30,641
Total non-interest expense	80,601	73,713	149,510	149,339
Income before income taxes	66,705	53,822	134,381	101,946
Provision for income taxes	13,818	13,253	28,074	29,373
Net income	$ 52,887	$ 40,569	$ 106,307	$ 72,573
Basic earnings per common share:
Weighted average number of shares outstanding (in shares)	66,114,497	66,053,741	66,103,499	66,024,135
Net income (in dollars per share)	$ 0.80	$ 0.61	$ 1.61	$ 1.10
Fully diluted earnings per common share:
Weighted average number of shares outstanding (in shares)	66,932,113	66,715,171	66,898,065	66,731,499
Net income (in dollars per share)	$ 0.79	$ 0.61	$ 1.59	$ 1.09
Services charges on deposit accounts
Non-interest income:
Service charges	$ 17,555	$ 17,882	$ 35,267	$ 35,788
Other service charges, commissions and fees, Banking
Non-interest income:
Service charges	11,152	11,025	22,274	21,410
Other service charges, commissions and fees, Non-banking
Non-interest income:
Service charges	$ 2,028	$ 1,864	$ 3,388	$ 3,199