Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
ASSETS
Cash and due from banks	$ 91,889		$ 124,573
Interest-earning deposits with banks	356,056		389,353
Total cash and cash equivalents	447,945		513,926
Securities available for sale at fair value (amortized cost of $984,075 and $969,359, respectively)	1,012,162		1,001,665
Federal Home Loan Bank stock at cost	21,621		21,819
Loans held for sale	888		2,563
Loans, net	2,933,306		2,864,803
FDIC loss sharing asset	83,115		96,354
Interest receivable	16,321		14,268
Premises and equipment, net	120,665		118,708
Other real estate owned ($13,811 and $16,311 covered by FDIC loss share, respectively)	25,727		26,987
Goodwill	115,554		115,554
Core deposit intangible, net	14,693		15,721
Other assets	113,014		113,967
Total Assets	4,905,011		4,906,335
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing	1,274,330		1,321,171
Interest-bearing	2,772,209		2,720,914
Total deposits	4,046,539		4,042,085
Federal Home Loan Bank advances	6,634		6,644
Securities sold under agreements to repurchase	25,000		25,000
Other liabilities	57,178		68,598
Total liabilities	4,135,351		4,142,327
Commitments and contingent liabilities
Shareholders' equity:
Authorized shares	63,033		63,033
Common Stock Shares Issued And Outstanding	39,844		39,686
Common Stock (no par value)	582,348		581,471
Retained earnings	170,593		162,388
Accumulated other comprehensive income	16,719	[1]	20,149	[1]
Total shareholders' equity	769,660		764,008
Total Liabilities and Shareholders' Equity	4,905,011		4,906,335
Noncovered Loans [Member]
ASSETS
Loans held for sale	888		2,563
Loans, excluding covered loans, net of unearned income of ($6,985) and ($7,767), respectively	2,621,212		2,525,710
Loans and Leases Receivable, Allowance	51,119		52,244
Loans, net	2,570,093		2,473,466
Other real estate owned ($13,811 and $16,311 covered by FDIC loss share, respectively)	11,916		10,676
Covered Loans [Member]
ASSETS
Loans and Leases Receivable, Allowance	29,489		30,056
Loans, net	363,213		391,337
Other real estate owned ($13,811 and $16,311 covered by FDIC loss share, respectively)	$ 13,811		$ 16,311

[1] All amounts are net of tax. Amounts in parenthesis indicate debits.