CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Operating activities:
Net income	$ 58,264	$ 54,154
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	8,487	8,608
Amortization of intangible assets	3,343	3,251
Net accretion of premiums & discounts on securities, loans and borrowings	(4,167)	(1,356)
Stock-based compensation	2,855	3,038
Provision for loan losses	6,442	3,143
Amortization of mortgage servicing rights	536	667
Income on bank-owned life insurance policies	(833)	(581)
Gain on investment securities and debt extinguishments, net	(291)	(8)
Net loss/(gain) from sale of loans and other assets	229	(281)
Net change in loans held for sale	488	4,410
Change in other assets and liabilities	12,815	5,555
Net cash provided by operating activities	88,168	80,600
Investing activities:
Proceeds from sales of available-for-sale investment securities	5,378	13,371
Proceeds from maturities of available-for-sale investment securities	144,958	151,997
Proceeds from maturities of held-to-maturity investment securities	20,517	54,152
Proceeds from maturities of other investment securities	275	1,197
Purchases of available-for-sale investment securities	(745,074)	(176,188)
Purchases of held-to-maturity investment securities	(107,317)	(7,424)
Purchases of other securities	(14)	(3,075)
Net (increase) decrease in loans	(187,154)	9,038
Cash received from acquisition, net of cash paid of $0 and $20,704	600,972	6,197
Purchases of premises and equipment	(7,103)	(6,895)
Net cash used in investing activities	(274,562)	42,370
Financing activities:
Net increase in deposits	115,422	133,154
Net decrease in borrowings	(165)	(19,884)
Issuance of common stock	62,873	2,273
Sale of treasury stock	210	0
Cash dividends paid	(30,084)	(24,828)
Tax benefits from share-based payment arrangements	1,013	355
Net cash provided by financing activities	149,269	91,070
Change in cash and cash equivalents	(37,125)	214,040
Cash and cash equivalents at beginning of period	324,878	211,837
Cash and cash equivalents at end of period	287,753	425,877
Supplemental disclosures of cash flow information:
Cash paid for interest	39,355	45,970
Cash paid for income taxes	16,217	14,750
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	10,682	9,575
Transfers from loans to other real estate	2,571	4,011
Acquisitions
Fair value of assets acquired, excluding acquired cash and intangibles	165,885	815,828
Fair value of liabilities assumed	$ 798,031	$ 791,222