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
Interest and fees on loans	$ 188,875	$ 165,388	$ 372,167	$ 322,206
Interest on investment securities:
Taxable	21,214	14,706	41,715	27,125
Tax-exempt	7,297	5,998	14,467	11,554
Dividends on nonmarketable equity securities	2,401	2,189	4,139	4,090
Interest on deposits with the Federal Reserve Bank and other banks and federal funds sold	1,641	1,301	2,921	2,541
Total interest income	221,428	189,582	435,409	367,516
Interest expense
Interest on deposits	42,011	19,707	81,009	35,624
Interest on collateralized customer deposits	537	641	1,164	1,165
Interest on short-term borrowings	11,345	10,408	20,523	18,574
Interest on long-term borrowings	2,374	1,289	4,728	2,753
Total interest expense	56,267	32,045	107,424	58,116
Net interest income	165,161	157,537	327,985	309,400
Provision for loan losses	7,502	9,572	9,561	15,828
Net interest income after provision for loan losses	157,659	147,965	318,424	293,572
Noninterest income
Net gain on sale of loans and other mortgage banking revenue	4,532	8,844	5,426	21,379
Net gain on sale of investment securities	4,160	3	4,247	3
Other	8,504	7,494	13,717	14,985
Total noninterest income	38,164	38,018	63,021	78,572
Operating expenses
Salaries, wages and employee benefits	62,129	56,148	122,146	111,705
Occupancy	7,786	7,679	16,063	15,690
Equipment and software	7,076	8,276	14,055	15,935
Outside processing and service fees	12,206	10,673	23,932	21,029
Merger expenses	3,042	0	8,466	0
Other	18,764	21,785	35,356	41,812
Total operating expenses	111,003	104,561	220,018	206,171
Income before income taxes	84,820	81,422	161,427	165,973
Income tax expense	15,226	12,434	28,891	25,389
Net income	$ 69,594	$ 68,988	$ 132,536	$ 140,584
Earnings per common share:
Basic earnings per common share (dollars per share)	$ 0.97	$ 0.97	$ 1.85	$ 1.97
Diluted earnings per common share (dollars per share)	$ 0.96	$ 0.96	$ 1.84	$ 1.95
Service charges and fees on deposit accounts
Noninterest income
Noninterest income	$ 8,247	$ 9,690	$ 16,214	$ 19,124
Wealth management revenue
Noninterest income
Noninterest income	6,966	7,188	12,838	13,499
Other charges and fees for customer services
Noninterest income
Noninterest income	$ 5,755	$ 4,799	$ 10,579	$ 9,582