Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 355,072	$ 386,948
Interest-bearing bank deposits	103,763	92,157
Federal funds sold	447	227
Securities available for sale, at fair value (amortized cost of $3,091,620 and $2,949,057)	2,981,673	2,910,869
Securities held to maturity (fair value of $3,054,469 and $2,962,010)	3,132,200	2,977,511
Loans held for sale	36,047	39,865
Loans	19,370,917	19,004,163
Less: allowance for loan losses	(214,530)	(217,308)
Loans, net	19,156,387	18,786,855
Property and equipment, net of accumulated depreciation of $218,526 and $214,998	336,513	333,663
Prepaid expenses	31,232	28,015
Other real estate, net	9,675	14,862
Accrued interest receivable	80,982	82,191
Goodwill	745,523	745,523
Other intangible assets, net	79,700	90,640
Life insurance contracts	546,395	541,081
Deferred tax asset, net	53,510	53,979
Other assets	276,328	251,700
Total assets	27,925,447	27,336,086
Deposits
Noninterest-bearing	8,165,796	8,307,497
Interest-bearing	14,069,542	13,945,705
Total deposits	22,235,338	22,253,202
Short-term borrowings	2,314,190	1,703,890
Long-term debt	266,009	305,513
Accrued interest payable	14,145	8,680
Other liabilities	166,210	179,852
Total liabilities	24,995,892	24,451,137
Stockholders' equity:
Common Stock	292,716	292,716
Capital surplus	1,729,542	1,718,117
Retained earnings	1,110,506	1,008,518
Accumulated other comprehensive loss, net	(203,209)	(134,402)
Total stockholders' equity	2,929,555	2,884,949
Total liabilities and stockholders' equity	$ 27,925,447	$ 27,336,086
Common shares authorized (par value of 3.33 per share)	350,000	350,000
Common shares issued	87,903	87,903
Common shares outstanding	85,335	85,200