Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 128,640	$ 104,783
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,178	25,228
Provision for loan losses	25,404	26,141
Losses on other real estate owned	3,519	17,901
Writedowns on closed branch transfers to other real estate owned	8,450	4,586
Deferred tax expense	20,807	35,557
Increase in cash surrender value of life insurance contracts	(8,764)	(8,617)
Net decrease in loans originated for sale	35,497	21,989
Net amortization of securities premium/discount	27,095	38,241
Amortization of intangible assets	22,292	24,390
Stock-based compensation expense	10,435	7,718
Increase (decrease) in interest payable and other liabilities	7,673	(38,797)
Funds collected under FDIC loss share agreements	60,886	84,130
Increase in FDIC loss share receivable	(7,108)	(55,690)
Decrease in other assets	43,091	34,322
Other, net	9,092	(2,132)
Net cash provided by operating activities	411,187	319,750
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale		37,661
Proceeds from maturities of securities available for sale	510,886	880,438
Purchases of securities available for sale	(1,017,578)	(208,775)
Proceeds from maturities of securities held to maturity	419,334	263,357
Purchases of securities held to maturity	(450,661)	(560,435)
Net decrease in interest-bearing bank deposits	1,052,369	865,590
Net increase in federal funds sold and short term investments	(14,493)	(1,228)
Net increase in loans	(229,913)	(324,495)
Purchases of property, equipment and intangible assets	(25,855)	(34,815)
Proceeds from sales of other real estate	70,220	76,427
Other, net	(7,280)	5,919
Net cash provided by investing activities	307,029	999,644
CASH FLOWS FROM FINANCING ACTIVITIES:
Net decrease in deposits	(689,317)	(940,629)
Net increase (decrease) in short-term borrowings	143,646	(295,820)
Repayments of long-term debt	(26,469)	(52,065)
Issuance of long-term debt	6,544	6,502
Dividends paid	(61,000)	(61,916)
Repurchase of common stock	(115,000)
Proceeds from exercise of stock options	582	1,210
Net cash used in financing activities	(741,014)	(1,342,718)
NET DECREASE IN CASH AND DUE FROM BANKS	(22,798)	(23,324)
CASH AND DUE FROM BANKS, BEGINNING	448,491	437,947
CASH AND DUE FROM BANKS, ENDING	425,693	414,623
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	42,070	63,917
Transfers from available for sale securities to held to maturity securities	$ 983,162	$ 1,523,585