Note 4 - Loans (Detail) - Loan Portfolio (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Commercial and industrial	$ 1,458,446		$ 1,465,903
Agricultural	243,776		227,756
Commercial real estate:
Office, retail, and industrial	1,299,082		1,203,613
Multi-family	288,336		349,862
Residential construction	105,836		174,690
Commercial construction	144,909		164,472
Other commercial real estate	888,146		856,357
Total commercial real estate	2,726,309		2,748,994
Total corporate loans	4,428,531		4,442,653
Home equity	416,194		445,243
1-4 family mortgages	201,099		160,890
Installment loans	42,289		51,774
Total consumer loans	659,582		657,907
Total loans, excluding covered loans	5,088,113		5,100,560
Covered loans (1)	260,502	[1]	371,729	[1]
Total loans	5,348,615		5,472,289
Deferred loan fees included in total loans	7,828		8,042
Overdrawn demand deposits included in total loans	$ 2,850		$ 4,281

[1] For information on covered loans, refer to Note 5, "Covered Assets."