Note 4 - Loans and Allowance for Loan Losses (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Impaired Financing Receivable, Recorded Investment	$ 33,948,000		$ 33,948,000		$ 40,108,000
Impaired Financing Receivable, Related Allowance	3,291,000		3,291,000		3,483,000
Impaired Financing Receivable, Interest Income, Accrual Method	406,000	518,000	1,310,000	1,583,000
Impaired Financing Receivable, Average Recorded Investment	33,952,000	46,932,000	35,771,000	48,310,000
Financing Receivable, Modifications, Number of Contracts	30		30		37
Risk Ratings 6,7, and 8 [Member]
Loans And Leases Receivable Classified	45,500,000		45,500,000		60,600,000
Loans Receivable [Member]
Loans and Leases Receivable, Gross	1,860,000,000		1,860,000,000		1,740,000,000
Student Loans [Member]
Loans and Leases Receivable, Gross	36,441,000		36,441,000		47,419,000
Percentage of Portfolio	97.00%		97.00%
Impaired Financing Receivable, Recorded Investment	70,000		70,000
Impaired Financing Receivable, Related Allowance	2,000		2,000
Restructured During Current Period [Member]
Financing Receivable, Modifications, Number of Contracts	6		6
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 1,200,000		$ 1,200,000