Note 7 - Loans (Detail) - Troubled Debt Restructurings Modified (USD $)	12 Months Ended				3 Months Ended				3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Accruing Troubled Debt Restructuring Member Commercial Loans Member	Mar. 31, 2012 Accruing Troubled Debt Restructuring Member Commercial Loans Member	Mar. 31, 2012 Accruing Troubled Debt Restructuring Member Commercial Mortgage Loans [Member]	Mar. 31, 2013 Accruing Troubled Debt Restructuring Member Commercial Mortgage Loans [Member]	Mar. 31, 2013 Accruing Troubled Debt Restructuring Member Residential Mortgage Loans [Member]	Mar. 31, 2012 Accruing Troubled Debt Restructuring Member Residential Mortgage Loans [Member]	Mar. 31, 2012 Accruing Troubled Debt Restructuring Member Total [Member]	Mar. 31, 2013 Accruing Troubled Debt Restructuring Member Total [Member]	Mar. 31, 2013 Accruing Troubled Debt Restructuring Member	Dec. 31, 2012 Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Accruing Troubled Debt Restructuring Member
No. of Loans			4	5	9	2	6	2	16	12
Pre-Modification Recorded Investment			$ 4,007,000	$ 1,988,000	$ 26,693,000	$ 1,175,000	$ 1,696,000	$ 1,587,000	$ 30,268,000	$ 6,878,000
Post-Modification Recorded Investment			4,007,000	1,988,000	23,375,000	1,175,000	1,696,000	1,587,000	26,950,000	6,878,000	130,215,000	144,695,000	143,233,000	120,016,000
Charge-offs	0				3,318,000				3,318,000
Specific Reserve	$ 17,357,000	$ 12,183,000	$ 61,000	$ 68,000	$ 268,000	$ 10,000	$ 265,000		$ 336,000	$ 336,000