Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Cash and cash equivalents:
Cash and due from banks	$ 212,042	$ 201,966	$ 183,170
Interest-bearing deposits with banks	348,602	36,241	250,229
Federal funds sold and securities purchased under agreements to resell	102,482	136,241	263,878
Total cash and cash equivalents	663,126	374,448	697,277
Investment securities:
Securities held to maturity (fair value of $6,217, $6,250 and $8,280, respectively)	6,095	6,094	7,920
Securities available for sale, at fair value	1,381,013	999,405	978,047
Other investments	13,501	9,482	9,539
Total investment securities	1,400,609	1,014,981	995,506
Loans held for sale	46,988	50,572	34,933
Loans:
Loans, net	7,868,840	6,643,326	6,129,228
FDIC indemnification asset			2,091
Other real estate owned (covered of $0, $0 and $4,222, respectively; non-covered of $20,007, $18,316 and $21,731, respectively)	20,007	18,316	25,953
Premises and equipment, net	203,505	183,510	176,412
Bank owned life insurance	149,562	104,148	102,199
Deferred tax assets	43,075	31,123	32,045
Mortgage servicing rights	30,063	29,037	23,697
Core deposit and other intangibles	55,461	39,848	45,521
Goodwill	595,711	338,340	338,340
Other assets	73,123	72,943	67,555
Total assets	11,150,070	8,900,592	8,670,757
Deposits:
Noninterest-bearing	2,599,111	2,199,046	2,020,632
Interest-bearing	6,434,327	5,135,377	5,141,316
Total deposits	9,033,438	7,334,423	7,161,948
Federal funds purchased and securities sold under agreements to repurchase	352,431	313,773	312,034
Other borrowings	107,988	55,358	55,210
Other liabilities	76,313	62,450	59,511
Total liabilities	9,570,170	7,766,004	7,588,703
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; 29,230,734, 24,230,392 and 24,177,833 shares issued and outstanding, respectively	73,077	60,576	60,445
Surplus	1,132,173	711,307	701,462
Retained earnings	379,534	370,916	316,642
Accumulated other comprehensive income (loss)	(4,884)	(8,211)	3,505
Total shareholders' equity	1,579,900	1,134,588	1,082,054
Total liabilities and shareholders' equity	11,150,070	8,900,592	8,670,757
Acquired credit impaired loans
Loans:
Loans, net	627,340	602,546	692,437
Total loans	631,896		696,314
Loans, net	627,340	602,546	598,601
Non-acquired loans
Loans:
Total loans	5,564,307	5,241,041	4,472,668
Less allowance for non-acquired loan losses	(38,449)	(36,960)	(35,115)
Loans, net	5,525,858	5,204,081	4,437,553
Acquired non-credit impaired loans
Loans:
Loans, net	1,715,642	836,699	999,238
Total loans	1,715,642		999,238
Loans, net	$ 1,715,642	$ 836,699	$ 991,505