Note 6 - Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Detail) - Impaired Loans Individually Evaluated by Class (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Impaired Loans	$ 81,750	$ 159,487
Loans With No Specific Related Allowance [Member] | Commercial And Industrial [Member]
Impaired Loans	9,707	10,801	[1]
Loans With No Specific Related Allowance [Member] | Agricultural [Member]
Impaired Loans	724	556	[1]
Loans With No Specific Related Allowance [Member] | Office Retail And Industrial [Member]
Impaired Loans	9,540	11,897
Loans With No Specific Related Allowance [Member] | Multi-Family [Member]
Impaired Loans	646	5,072	[1]
Loans With No Specific Related Allowance [Member] | Residential Construction [Member]
Impaired Loans	4,009	9,718	[1]
Loans With No Specific Related Allowance [Member] | Commercial Construction [Member]
Impaired Loans	3,550	19,019	[1]
Loans With No Specific Related Allowance [Member] | Other Commerical Real Estate [Member]
Impaired Loans	7,431	26,027	[1]
Loans With No Specific Related Allowance [Member] | Total Commercial Real Estate [Member]
Impaired Loans	25,176	71,733	[1]
Loans With No Specific Related Allowance [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans	35,607	83,090	[1]
Loans With A Related Allowance For Credit Losses [Member] | Commercial And Industrial [Member]
Impaired Loans	19,023	26,028
Loans With A Related Allowance For Credit Losses [Member] | Office Retail And Industrial [Member]
Impaired Loans	12,496	16,319
Loans With A Related Allowance For Credit Losses [Member] | Multi-Family [Member]
Impaired Loans	801	517
Loans With A Related Allowance For Credit Losses [Member] | Residential Construction [Member]
Impaired Loans	503	7,660
Loans With A Related Allowance For Credit Losses [Member] | Commercial Construction [Member]
Impaired Loans	876	3,790
Loans With A Related Allowance For Credit Losses [Member] | Other Commerical Real Estate [Member]
Impaired Loans	12,444	22,083
Loans With A Related Allowance For Credit Losses [Member] | Total Commercial Real Estate [Member]
Impaired Loans	27,120	50,369
Loans With A Related Allowance For Credit Losses [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans	46,143	76,397
Unpaid Principal Balance [Member] | Commercial And Industrial [Member]
Impaired Loans	60,808	58,591
Unpaid Principal Balance [Member] | Agricultural [Member]
Impaired Loans	892	556
Unpaid Principal Balance [Member] | Office Retail And Industrial [Member]
Impaired Loans	38,896	33,785
Unpaid Principal Balance [Member] | Multi-Family [Member]
Impaired Loans	3,433	11,265
Unpaid Principal Balance [Member] | Residential Construction [Member]
Impaired Loans	12,134	33,124
Unpaid Principal Balance [Member] | Commercial Construction [Member]
Impaired Loans	9,139	28,534
Unpaid Principal Balance [Member] | Other Commerical Real Estate [Member]
Impaired Loans	29,701	70,868
Unpaid Principal Balance [Member] | Total Commercial Real Estate [Member]
Impaired Loans	93,303	177,576
Unpaid Principal Balance [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans	155,003	236,723
Allowance For Credit Losses Allocated [Member] | Commercial And Industrial [Member]
Impaired Loans	10,627	14,827
Allowance For Credit Losses Allocated [Member] | Office Retail And Industrial [Member]
Impaired Loans	1,413	1,507
Allowance For Credit Losses Allocated [Member] | Multi-Family [Member]
Impaired Loans	80	20
Allowance For Credit Losses Allocated [Member] | Residential Construction [Member]
Impaired Loans	173	2,502
Allowance For Credit Losses Allocated [Member] | Commercial Construction [Member]
Impaired Loans	37	758
Allowance For Credit Losses Allocated [Member] | Other Commerical Real Estate [Member]
Impaired Loans	1,658	6,481
Allowance For Credit Losses Allocated [Member] | Total Commercial Real Estate [Member]
Impaired Loans	3,361	11,268
Allowance For Credit Losses Allocated [Member] | Total Impaired Loans Individually Evaluated For Impairment [Member]
Impaired Loans	$ 13,988	$ 26,095

[1] No specific allowance for credit losses is allocated to these loans since they are deemed to be sufficiently collateralized or had charge-offs. However, while each component of the allowance for credit losses is determined separately, the entire balance is available for the entire loan portfolio.