Note 6 - Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Impaired Loans Individually Evaluated by Class (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	$ 0	$ 0
Recorded investment in loans with a specific reserve	0	0
Unpaid principal balance	0	0
Specific reserve	0	0
Office Retail And Industrial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	19,133	14,504
Recorded investment in loans with a specific reserve	3,762	7,232
Unpaid principal balance	31,736	29,631
Specific reserve	1,081	971
Multi-Family [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	902	642
Recorded investment in loans with a specific reserve	145	0
Unpaid principal balance	3,045	2,406
Specific reserve	157	0
Residential Construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	2,032	4,040
Recorded investment in loans with a specific reserve	870	0
Unpaid principal balance	7,200	10,741
Specific reserve	59	0
Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	3,881	0
Recorded investment in loans with a specific reserve	0	876
Unpaid principal balance	4,247	1,242
Specific reserve	0	90
Other Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	8,588	5,218
Recorded investment in loans with a specific reserve	2,834	10,066
Unpaid principal balance	15,479	23,907
Specific reserve	636	1,157
Total Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	34,536	24,404
Recorded investment in loans with a specific reserve	7,611	18,174
Unpaid principal balance	61,707	67,927
Specific reserve	1,933	2,218
Total Impaired Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	55,171	30,040
Recorded investment in loans with a specific reserve	12,103	36,269
Unpaid principal balance	102,696	107,761
Specific reserve	5,620	11,622
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment in loans with no specific reserve	20,635	5,636
Recorded investment in loans with a specific reserve	4,492	18,095
Unpaid principal balance	40,989	39,834
Specific reserve	$ 3,687	$ 9,404