Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
ASSETS
Cash and due from banks	$ 191,706		$ 165,030
Interest-earning deposits with banks	45,083		14,531
Total cash and cash equivalents	236,789		179,561
Securities available for sale at fair value (amortized cost of $1,644,805 and $1,680,491, respectively)	1,639,370		1,664,111
Federal Home Loan Bank stock at cost	32,224		32,529
Loans held for sale	0		735
Loans, net	4,506,792		4,444,842
FDIC loss sharing asset	36,837		39,846
Interest receivable	23,600		22,206
Premises and equipment, net	156,836		154,732
Other real estate owned ($14,712 and $12,093 covered by FDIC loss share, respectively)	30,552		35,927
Goodwill	343,952		343,952
Intangible Assets, Net (Excluding Goodwill)	24,273		25,852
Other assets	205,828		217,289
Total Assets	7,237,053		7,161,582
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing	2,225,212		2,171,703
Interest-bearing	3,819,204		3,787,772
Total deposits	6,044,416		5,959,475
Federal Home Loan Bank advances	6,597		36,606
Securities sold under agreements to repurchase	25,000		25,000
Other liabilities	86,549		87,252
Total liabilities	6,162,562		6,108,333
Commitments and contingent liabilities
Preferred Stock, Shares Authorized	2,000		2,000
Preferred Stock, Shares Issued	9		9
Preferred Stock, Value, Issued	2,217		2,217
Shareholders' equity:
Authorized shares	63,033		63,033
Common Stock Shares Issued And Outstanding	52,600		51,265
Common Stock (no par value)	861,125		860,562
Retained earnings	216,192		202,514
Accumulated other comprehensive income	(5,043)	[1]	(12,044)	[1]
Total shareholders' equity	1,074,491		1,053,249
Total Liabilities and Shareholders' Equity	7,237,053		7,161,582
Noncovered Loans [Member]
ASSETS
Loans held for sale	0		735
Loans, excluding covered loans, net of unearned income of ($62,724) and ($68,282), respectively	4,297,076		4,219,451
Loans and Leases Receivable, Allowance	50,442		52,280
Loans, net	4,246,634		4,167,171
Other real estate owned ($14,712 and $12,093 covered by FDIC loss share, respectively)	15,840		23,834
Covered Loans [Member]
ASSETS
Loans and Leases Receivable, Allowance	20,129		20,174
Loans, net	260,158		277,671
Other real estate owned ($14,712 and $12,093 covered by FDIC loss share, respectively)	$ 14,712		$ 12,093

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