Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Cash and cash equivalents:
Cash and due from banks	$ 182,875	$ 178,664	$ 155,881
Interest-bearing deposits with banks	8,055	218,883	273,273
Federal funds sold and securities purchased under agreements to resell	290,982	298,247	164,228
Total cash and cash equivalents	481,912	695,794	593,382
Investment securities:
Securities held to maturity (fair value of $8,280, $9,723 and $10,232, respectively)	7,921	9,314	9,659
Securities available for sale, at fair value	989,610	1,009,541	841,661
Other investments	9,529	8,893	9,031
Total investment securities	1,007,060	1,027,748	860,351
Loans held for sale	48,926	41,649	73,055
Loans:
Loans, net	6,380,657	5,970,044	5,749,270
Loans, gross	4,816,875	4,220,726	3,788,399
Less allowance for non-acquired loan losses	(36,939)	(34,090)	(34,782)
FDIC indemnification asset		4,401	11,035
Other real estate owned (covered of $0, $5,751 and $8,172, respectively; non-covered of $22,427, $24,803 and $26,870, respectively)	22,427	30,554	35,042
Premises and equipment, net	177,950	174,537	171,582
Bank owned life insurance	102,815	101,588	100,363
Deferred tax assets	25,915	37,827	45,911
Mortgage servicing rights	22,350	26,202	25,325
Core deposit and other intangibles	43,629	47,425	45,260
Goodwill	338,340	338,340	317,688
Other assets	72,012	61,239	56,720
Total assets	8,723,993	8,557,348	8,084,984
Deposits:
Noninterest-bearing	2,117,246	1,976,480	1,844,973
Interest-bearing	5,046,680	5,123,948	4,822,555
Total deposits	7,163,926	7,100,428	6,667,528
Federal funds purchased and securities sold under agreements to repurchase	341,064	288,231	287,903
Other borrowings	55,254	55,158	55,055
Other liabilities	59,406	54,147	50,719
Total liabilities	7,619,650	7,497,964	7,061,205
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; 24,195,226, 24,162,657 and 24,197,531 shares issued and outstanding, respectively	60,488	60,407	60,494
Surplus	703,445	703,929	704,625
Retained earnings	333,900	298,919	260,591
Accumulated other comprehensive loss	6,510	(3,871)	(1,931)
Total shareholders' equity	1,104,343	1,059,384	1,023,779
Total liabilities and shareholders' equity	8,723,993	8,557,348	8,084,984
Acquired credit impaired loans
Loans:
Loans, net	658,835	733,870	823,981
Acquired non-credit impaired loans
Loans:
Loans, net	$ 941,886	$ 1,049,538	$ 1,171,672