Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
OPERATING ACTIVITIES
Net income	$ 138,562	$ 166,869		$ 132,395
Adjustments to reconcile net income to cash provided by operating activities:
Provision for loan and lease losses	640	(32,255)		142,885
Deferred tax expense (benefit)	(33,339)	47,646		(34,422)
Change in current taxes payable	72,274	(79,173)		29,095
Depreciation	75,481	70,841		68,941
Change in accrued interest payable	1,457	(2,616)		(14,366)
Change in income earned not collected	6,402	(724)		(5,450)
Gain on sale of other assets	0	(4,085)		0
Securities losses (gains)	(29,096)	0		(2,277)
Origination of loans held for sale	(377,993)	(393,908)		(575,705)
Proceeds from sale of loans held for sale	398,719	443,708		589,376
Gain on sale of loans	(4,971)	(10,738)		(7,465)
Loss on sale of other real estate	14,275	6,686		36,229
Gain on elimination of acquired debt	(1,988)	0		0
Net amortization of premiums and discounts	(48,374)	(112,759)		(156,796)
Amortization of intangible assets	6,955	2,309		3,476
FDIC receivable for loss share agreements	27,666	71,771		(7,181)
FDIC payable for loss share agreements	6,933	7,821		101,557
Net change in other assets	(72,680)	100,437		(21,414)
Net change in other liabilities	1,319	49,177		(77,590)
Net cash provided by operating activities	182,242	331,007		201,288
INVESTING ACTIVITIES
Net change in loans outstanding	(814,372)	323,436		627,806
Purchases of investment securities available for sale	(2,518,680)	(2,671,420)		(5,169,641)
Proceeds from maturities of investment securities held to maturity	389	435		480
Proceeds from maturities of investment securities available for sale	2,482,722	2,437,851		3,986,370
Proceeds from sales of investment securities available for sale	422,652	0		7,900
Net change in overnight investments	221,730	(416,144)		(8,205)
Cash (paid to) received from the FDIC for loss share agreements	(1,286)	19,373		251,972
Proceeds from Sale of Other Real Estate	89,485	147,550		147,858
Additions to premises and equipment	(82,708)	(66,037)		(88,883)
Business acquisition, net of cash acquired	182,370	0		0
Net cash (used) provided by investing activities	(17,698)	(224,956)		(244,343)
FINANCING ACTIVITIES
Net change in time deposits	(499,869)	(699,005)		(1,049,761)
Net change in demand and other interest-bearing deposits	497,692	487,046		1,558,512
Net change in short-term borrowings	(25,321)	(57,087)		(101,717)
Repayment of long-term obligations	(54,301)	(4,152)		(196,338)
Origination of long-term obligations	0	70,000		310
Stock issuance costs	(619)	0		0
Repurchase of common stock	0	(321)		(103,624)
Cash dividends paid	(11,543)	(8,663)		(15,398)
Net cash provided (used) by financing activities	(93,961)	(212,182)		91,984
Change in cash and due from banks	70,583	(106,131)		48,929
Cash and due from banks at beginning of period	533,599	639,730		590,801
Cash and due from banks at end of period	604,182	533,599		639,730
CASH PAYMENTS FOR:
Interest	48,894	59,234		104,514
Income taxes	127,970	102,890		66,453
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Transfers of loans to other real estate	65,956	92,125		140,645
Dividends declared but not paid	3,603	2,885		0
Reclassification of reserve for unfunded commitments to allowance for loans and leases	0	7,368	[1]	0
Repurchase and retirement of common stock	(46,085)	0		0
Issuance of common stock associated with Bancorporation merger	$ 564,248	$ 0		$ 0

[1] Reclassification results from enhancements to the ALLL calculation during the second quarter of 2013 that resulted in the allocation of $15.8 million previously designated as 'nonspecific' to other loan classes and the absorption of $7.4 million of the reserve for unfunded commitments related to unfunded, revocable loan commitments into the ALLL. Further discussion is contained in Note A.