Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities
Net income	$ 57,901	$ 57,404	$ 52,011
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan and lease losses	20,737	29,809	33,392
Depreciation and amortization of premises and equipment	5,463	5,327	5,398
Net accretion on securities	1,597	1,468	535
Amortization of intangible assets	3,046	3,072	3,246
Stock based compensation	3,244	3,782	3,133
Bank owned life insurance income	(3,085)	(3,316)	(3,135)
Trading security purchases	(447)	(184)	(460)
Unrealized losses (gains) in trading securities	193	(214)	(543)
Deferred income tax benefit	(9,478)	(14,955)	(1,501)
Proceeds from sale of loans held for sale	13,545	83,143	135,519
Originations and purchases of loans held for sale	(14,167)	(80,469)	(138,583)
Net gains on sales of loans held for sale	(329)	(911)	(953)
Net security gains	(150)	(3,274)	(144)
Net gains on sales of other real estate owned	(2,531)	(517)	(306)
Net (increase) decrease in other assets	(3,579)	6,627	(39,324)
Net increase in other liabilities	11,805	2,645	6,399
Net cash provided by operating activities	83,765	89,437	54,684
Investing activities
Net cash provided by acquisitions	81,467	0	0
Securities available for sale:
Proceeds from maturities, calls, and principal paydowns	541,555	511,394	434,127
Proceeds from sales	2,437	103,253	2,753
Purchases	(648,048)	(635,319)	(426,979)
Securities held to maturity:
Proceeds from maturities, calls, and principal paydowns	47,186	112,399	90,668
Purchases	(20,736)	(48,701)	(110,496)
Net (increase) decrease in loans	(172,920)	7,292	(18,775)
Net decrease in Federal Reserve and FHLB stock	226	8,733	3,066
Proceeds from bank owned life insurance	758	2,767	1,054
Purchases of premises and equipment, net	(9,954)	(6,510)	(6,378)
Proceeds from sales of other real estate owned	2,531	3,186	2,512
Net cash (used in) provided by investing activities	(175,498)	58,494	(28,448)
Financing activities
Net increase in deposits	87,992	41,306	169,788
Net increase (decrease) in short-term borrowings	22,158	3,457	(50,515)
Proceeds from issuance of long-term debt	156	0	0
Repayments of long-term debt	(2,146)	(184,824)	(77,511)
Excess tax benefit from exercise of stock options	341	140	(243)
Proceeds from the issuance of shares to employee benefit plans and other stock plans	1,386	1,675	2,728
Issuance of common stock	0	0	33,401
Purchase of treasury stock	(30,502)	(477)	0
Cash dividends and payments for fractional shares	(27,063)	(27,577)	(27,119)
Net cash provided by (used in) financing activities	52,322	(166,300)	50,529
Net (decrease) increase in cash and cash equivalents	(39,411)	(18,369)	76,765
Cash and cash equivalents at beginning of year	168,792	187,161	110,396
Cash and cash equivalents at end of year	129,381	168,792	187,161
Cash paid during the year for:
Interest	40,135	54,668	79,819
Income taxes, net of refund	31,258	37,033	13,952
Noncash investing activities:
Loans transferred to other real estate owned	2,927	1,212	3,899
Acquisitions:
Fair value of assets acquired	67,020	0	0
Fair value of liabilities assumed	$ 148,487	$ 0	$ 0