CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Activities
Net income	$ 34,941	$ 46,367
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	2,000	4,500
Depreciation and amortization	10,969	10,210
Deferred income tax benefit	(2,591)	(1,322)
Net increase in trading securities and other earning assets	(16,824)	(10,554)
Gains on sales of securities available for sale	(5,893)	(16,541)
Gains on sales of assets	303	(851)
Amortization of securities premiums, net of discount accretion	13,433	12,629
Originations of loans held for sale	(39,543)	(51,557)
Net gains on sales of loans held for sale	(211)	(304)
Proceeds from sales of loans held for sale	37,326	51,914
Issuance of equity awards	449	245
Equity based compensation	1,913	1,712
Changes in:
Accrued income	(761)	2,054
Accrued expenses and taxes	(11,956)	(19,282)
Other assets and liabilities, net	11,790	(19,069)
Net cash provided by operating activities	35,345	10,151
Investing Activities
Proceeds from maturities of securities held to maturity	7,996	2,163
Proceeds from sales of securities available for sale	333,912	775,658
Proceeds from maturities of securities available for sale	514,720	441,336
Purchases of securities held to maturity	(22,734)	(9,676)
Purchases of securities available for sale	(805,695)	(1,341,488)
Net increase in loans	(327,354)	(187,607)
Net decrease in fed funds sold and resell agreements	70,822	56,415
Net (increase) decrease in interest bearing balances due from other financial institutions	(1,004)	16,283
Purchases of bank premises and equipment	(8,011)	(6,880)
Net cash received from acquisitions	(692)	701
Proceeds from sales of bank premises and equipment	808	840
Net cash used in investing activities	(237,232)	(252,255)
Financing Activities
Net increase in demand and savings deposits	1,121,789	852,699
Net decrease in time deposits	(215,696)	(274,617)
Net decrease in fed funds purchased and repurchase agreements	(127,927)	(448,122)
Net decrease in short-term debt	(99)	(2,000)
Repayment of long-term debt	(972)	(1,106)
Payment of contingent consideration on acquisitions	(4,899)	(7,651)
Cash dividends paid	(8,526)	(8,302)
Net tax benefit related to equity compensation plans	332	84
Proceeds from exercise of stock options and sales of treasury shares	961	1,340
Purchases of treasury stock	(1,656)	(2,666)
Net cash provided by financing activities	763,307	109,659
Increase (decrease) in cash and due from banks	561,420	(132,445)
Cash and cash equivalents at beginning of period	1,366,394	1,459,631
Cash and cash equivalents at end of period	1,927,814	1,327,186
Supplemental Disclosures:
Income taxes paid	9,302	10,664
Total interest paid	$ 4,608	$ 6,213