CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest income:
Interest and fees on loans	$ 71,152	$ 62,351	$ 140,593	$ 114,735
Interest and dividends on taxable investments	16,517	15,175	32,041	28,741
Interest on nontaxable investments	3,336	3,896	6,775	7,904
Total interest income	91,005	81,422	179,409	151,380
Interest expense:
Interest on deposits	2,381	2,065	4,513	3,795
Interest on borrowings	446	392	926	541
Interest on subordinated debt held by unconsolidated subsidiary trusts	1,332	936	2,500	1,741
Total interest expense	4,159	3,393	7,939	6,077
Net interest income	86,846	78,029	171,470	145,303
Provision for loan losses	2,448	1,461	6,127	3,289
Net interest income after provision for loan losses	84,398	76,568	165,343	142,014
Noninterest revenues:
Deposit service fees	18,964	16,655	38,141	31,362
Other banking services	1,163	1,407	2,406	2,566
Employee benefit services	22,542	20,662	45,548	37,851
Insurance services	7,415	6,965	14,774	13,365
Wealth management services	6,496	5,537	13,202	10,398
Unrealized loss on equity securities	(21)	0	(21)	0
Gain on sales of investment securities	0	0	0	2
Total noninterest revenues	56,559	51,226	114,050	95,544
Noninterest expenses:
Salaries and employee benefits	52,402	46,564	104,261	89,471
Occupancy and equipment	9,437	8,637	19,968	16,833
Data processing and communications	10,212	10,395	18,954	18,916
Amortization of intangible assets	4,555	4,263	9,353	7,031
Legal and professional fees	2,745	2,619	5,525	5,033
Business development and marketing	2,654	2,451	4,714	4,532
Acquisition expenses	71	22,896	63	24,612
Other expenses	4,036	5,054	9,605	10,026
Total noninterest expenses	86,112	102,879	172,443	176,454
Income before income taxes	54,845	24,915	106,950	61,104
Income taxes	10,239	7,724	22,238	17,656
Net income	$ 44,606	$ 17,191	$ 84,712	$ 43,448
Basic earnings per share (in dollars per share)	$ 0.87	$ 0.35	$ 1.65	$ 0.92
Diluted earnings per share (in dollars per share)	0.86	0.35	1.63	0.91
Cash dividends declared per share (in dollars per share)	$ 0.34	$ 0.32	$ 0.68	$ 0.64