Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets:
Cash and due from banks	$ 386,948	$ 372,689
Interest-bearing bank deposits	92,157	77,235
Federal funds sold	227	942
Securities available for sale, at fair value (amortized cost of $2,949,057 and $2,562,000)	2,910,869	2,516,908
Securities held to maturity (fair value of $2,962,010 and $2,470,117)	2,977,511	2,500,220
Loans held for sale	39,865	34,064
Loans	19,004,163	16,752,151
Less: allowance for loan losses	(217,308)	(229,418)
Loans, net	18,786,855	16,522,733
Property and equipment, net of accumulated depreciation of $214,998 and $231,127	333,663	361,612
Prepaid expense	28,015	18,038
Other real estate, net	14,862	18,884
Accrued interest receivable	82,191	65,887
Goodwill	745,523	621,193
Other intangible assets, net	90,640	87,757
Life insurance contracts	541,081	480,406
FDIC loss share receivable		16,219
Deferred tax asset, net	53,979	104,435
Other assets	251,700	176,080
Total assets	27,336,086	23,975,302
Deposits:
Noninterest-bearing	8,307,497	7,658,203
Interest-bearing	13,945,705	11,766,063
Total deposits	22,253,202	19,424,266
Short-term borrowings	1,703,890	1,225,406
Long term debt	305,513	436,280
Accrued interest payable	8,680	9,574
Other liabilities	179,852	160,008
Total liabilities	24,451,137	21,255,534
Stockholders' equity:
Common Stock	292,716	291,358
Capital surplus	1,718,117	1,698,253
Retained earnings	1,008,518	850,689
Accumulated other comprehensive loss, net	(134,402)	(120,532)
Total stockholders' equity	2,884,949	2,719,768
Total liabilities and stockholders' equity	$ 27,336,086	$ 23,975,302
Common shares authorized (par value of 3.33 per share)	350,000	350,000
Common shares issued	87,903	87,495
Common shares outstanding	85,200	84,235