Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Cash and cash equivalents:
Cash and due from banks	$ 197,984	$ 201,966	$ 168,774
Interest-bearing deposits with banks	137,543	36,241	66,335
Federal funds sold and securities purchased under agreements to resell	68,407	136,241	272,408
Total cash and cash equivalents	403,934	374,448	507,517
Investment securities:
Securities held to maturity (fair value of $3,732, $6,250 and $7,076, respectively)	3,678	6,094	6,851
Securities available for sale, at fair value	1,320,679	999,405	925,374
Other investments	12,439	9,482	9,482
Total investment securities	1,336,796	1,014,981	941,707
Loans held for sale	46,321	50,572	57,052
Loans:
Loans, net	8,223,204	6,643,326	6,489,068
Other real estate owned	13,527	18,316	22,211
Premises and equipment, net	198,146	183,510	179,450
Bank owned life insurance	151,402	104,148	103,427
Deferred tax assets	41,664	31,123	25,357
Mortgage servicing rights	29,937	29,037	23,064
Core deposit and other intangibles	50,472	39,848	41,738
Goodwill	597,236	338,340	338,340
Other assets	76,471	72,943	68,234
Total assets	11,169,110	8,900,592	8,797,165
Deposits:
Noninterest-bearing	2,505,570	2,199,046	2,176,155
Interest-bearing	6,556,451	5,135,377	5,071,251
Total deposits	9,062,021	7,334,423	7,247,406
Federal funds purchased and securities sold under agreements to repurchase	291,099	313,773	305,268
Other borrowings	83,307	55,358	55,306
Other liabilities	99,858	62,450	65,053
Total liabilities	9,536,285	7,766,004	7,673,033
Shareholders' equity:
Preferred stock - $.01 par value; authorized 10,000,000 shares; no shares issued and outstanding
Common stock - $2.50 par value; authorized 40,000,000 shares; 29,267,369, 24,230,392 and 24,209,122 shares issued and outstanding, respectively	73,168	60,576	60,523
Surplus	1,136,352	711,307	705,124
Retained earnings	427,093	370,916	354,490
Accumulated other comprehensive income (loss)	(3,788)	(8,211)	3,995
Total shareholders' equity	1,632,825	1,134,588	1,124,132
Total liabilities and shareholders' equity	11,169,110	8,900,592	8,797,165
Acquired credit impaired loans
Loans:
Loans, net	578,863	602,546	632,617
Total loans	582,533		636,020
Non-acquired loans
Loans:
Total loans	6,230,327	5,241,041	5,008,113
Less allowance for non-acquired loan losses	(41,541)	(36,960)	(37,319)
Loans, net	6,188,786	5,204,081	4,970,794
Acquired non-credit impaired loans
Loans:
Loans, net	1,455,555	$ 836,699	885,657
Total loans	$ 1,455,555		$ 885,657