Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
OPERATING ACTIVITIES
Net income	$ 73,078	$ 83,060
Adjustments to reconcile net income to cash provided by operating activities:
Provision for loan and lease losses	60,382	98,396
Deferred tax (benefit) expense	(6,845)	(17,133)
Change in current taxes payable	26,247	19,774
Depreciation	33,326	32,408
Change in accrued interest payable	(626)	(5,755)
Change in income earned not collected	(7,527)	38,043
Gain on acquisitions	0	(63,474)
Securities losses (gains)	42	545
Origination of loans held for sale	(275,140)	(182,184)
Proceeds from sale of loans	294,163	218,533
Gain on sale of loans	(2,858)	(3,420)
Loss on sale of other real estate	453	1,349
Net amortization (accretion) of premiums and discounts	(117,610)	(83,552)
FDIC receivable for loss share agreements	225,461	239,621
Net change in other assets	56,180	93,818
Net change in other liabilities	4,076	(7,836)
Net cash provided by operating activities	362,802	462,193
INVESTING ACTIVITIES
Net change in loans outstanding	468,503	260,861
Purchases of investment securities available for sale	(2,914,481)	(632,041)
Proceeds from maturities of investment securities held to maturity	244	433
Proceeds from maturities of investment securities available for sale	2,328,204	1,214,988
Proceeds from sales of investment securities available for sale	56	191,697
Net change in overnight investments	(549,561)	(343,264)
Proceeds from sale of other real estate	78,820	24,748
Additions to premises and equipment	(49,253)	(32,574)
Net cash received from acquisitions	0	974,043
Net cash provided (used) by investing activities	(637,468)	1,658,891
FINANCING ACTIVITIES
Net change in time deposits	(528,819)	(617,419)
Net change in demand and other interest-bearing deposits	753,191	(959,739)
Net change in short-term borrowings	85,077	(227,642)
Repayment of long-term obligations	(45,997)	(224,915)
Repurchase of common stock	(2,414)	(7,575)
Cash dividends paid	(6,169)	(6,255)
Net cash provided (used) by financing activities	254,869	(2,043,545)
Change in cash and due from banks	(19,797)	77,539
Cash and due from banks at beginning of period	590,801	460,178
Cash and due from banks at end of period	571,004	537,717
CASH PAYMENTS FOR:
Interest	51,513	85,197
Income taxes	21,453	17,349
SUPPLEMENTAL DISCLOSURE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Change in unrealized securities gains (losses)	1,590	8,642
Change in fair value of cash flow hedge	(306)	(308)
Change in pension obligation	5,580	3,296
Transfers of loans to other real estate	80,413	77,780
Acquisitions:
Assets acquired	0	2,225,370
Liabilities assumed	0	2,161,896
Net assets acquired	$ 0	$ 63,474