Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Cash and due from banks	$ 333,314	$ 372,689
Interest-bearing bank deposits	50,452	77,235
Federal funds sold	821	942
Securities available for sale, at fair value (amortized cost of $2,541,535 and $2,562,000)	2,498,761	2,516,908
Securities held to maturity (fair value of $2,477,420 and $2,470,117)	2,502,512	2,500,220
Loans held for sale	20,883	34,064
Loans	18,204,868	16,752,151
Less: allowance for loan losses	(213,550)	(229,418)
Loans, net	17,991,318	16,522,733
Property and equipment, net of accumulated depreciation of $236,166 and $231,127	374,112	361,612
Prepaid expenses	22,033	18,038
Other real estate, net	17,068	18,884
Accrued interest receivable	70,975	65,887
Goodwill	716,761	621,193
Other intangible assets, net	86,952	87,757
Life insurance contracts	484,042	480,406
FDIC loss share receivable	13,320	16,219
Deferred tax asset, net	96,078	104,435
Other assets	205,624	176,080
Total assets	25,485,026	23,975,302
Deposits:
Noninterest-bearing	7,722,279	7,658,203
Interest-bearing	12,199,741	11,766,063
Total deposits	19,922,020	19,424,266
Short-term borrowings	2,121,932	1,225,406
Long-term debt	525,082	436,280
Accrued interest payable	10,476	9,574
Other liabilities	141,894	160,008
Total liabilities	22,721,404	21,255,534
Stockholders' equity:
Common Stock	291,358	291,358
Capital surplus	1,711,823	1,698,253
Retained earnings	878,953	850,689
Accumulated other comprehensive loss, net	(118,512)	(120,532)
Total stockholders' equity	2,763,622	2,719,768
Total liabilities and stockholders' equity	$ 25,485,026	$ 23,975,302
Common shares authorized (par value of 3.33 per share)	350,000	350,000
Common shares issued	87,495	87,495
Common shares outstanding	84,517	84,235