CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Operating Activities
Net income	$ 101,657	$ 83,206
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	13,500	17,200
Depreciation and amortization	30,576	32,720
Deferred income tax expense (benefit)	1,409	(3,740)
Net decrease (increase) in trading securities	18,223	(28,597)
Gains on sales of securities available for sale, net	(20,022)	(15,891)
(Gains) losses on sales of assets	(503)	61
Amortization of securities premiums, net of discount accretion	37,277	32,092
Originations of loans held for sale	(179,493)	(146,125)
Net gains on sales of loans held for sale	(1,526)	(1,139)
Proceeds from sales of loans held for sale	177,335	150,116
Issuance of equity awards	244	240
Equity based compensation	5,425	4,964
Changes in:
Accrued income	5,898	1,464
Accrued expenses and taxes	5,364	17,481
Other assets and liabilities, net	(18,305)	(11,170)
Net cash provided by operating activities	177,059	132,882
Investing Activities
Proceeds from maturities of securities held to maturity	6,327	7,153
Proceeds from sales of securities available for sale	991,842	991,014
Proceeds from maturities of securities available for sale	1,172,929	1,222,172
Purchases of securities held to maturity	(19,504)	(32,299)
Purchases of securities available for sale	(2,528,213)	(2,294,900)
Net increase in loans	(442,109)	(215,792)
Net decrease in fed funds sold and resell agreements	24,906	148,481
Net decrease in interest-bearing balances due from other financial institutions	121,079	35,523
Purchases of bank premises and equipment	(31,516)	(26,780)
Net cash received (paid) for acquisitions	1,529	(8,133)
Proceeds from sales of bank premises and equipment	1,034	160
Net cash used in investing activities	(701,696)	(173,401)
Financing Activities
Net increase in demand and savings deposits	864,852	716,953
Net decrease in time deposits	(421,983)	(350,671)
Net decrease in fed funds purchased and repurchase agreements	(786,628)	(743,649)
Net decrease in short-term debt	(12,000)	(3,331)
Proceeds from long-term debt	529	500
Repayment of long-term debt	(1,426)	(2,743)
Payment of contingent consideration on acquisitions	(12,260)	(8,316)
Cash dividends paid	(24,946)	(23,528)
Net tax benefit related to equity compensation plans	333	96
Proceeds from exercise of stock options and sales of treasury shares	6,071	1,226
Purchases of treasury stock	(6,062)	(8,435)
Net cash used in financing activities	(393,520)	(421,898)
Decrease in cash and due from banks	(918,157)	(462,417)
Cash and due from banks at beginning of period	1,459,631	1,033,617
Cash and due from banks at end of period	541,474	571,200
Supplemental Disclosures:
Income taxes paid	31,718	28,110
Total interest paid	$ 16,423	$ 21,781