Note 7 - Loans (Detail) - Troubled Debt Restructurings Modified (USD $) In Thousands, unless otherwise specified	3 Months Ended							3 Months Ended	12 Months Ended			12 Months Ended			3 Months Ended	12 Months Ended					3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Commercial Loans Member Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Commercial Loans Member Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Commercial Loans Member Non Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Commercial Loans Member Non Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Commercial Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Commercial Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Commercial Mortgage Loans [Member] Non Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Commercial Mortgage Loans [Member] Non Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Residential Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Residential Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Residential Mortgage Loans [Member] Non Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Total [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Total [Member] Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Total [Member] Non Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Total [Member] Non Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Accruing Troubled Debt Restructuring Member	Mar. 31, 2011 Accruing Troubled Debt Restructuring Member	Dec. 31, 2010 Accruing Troubled Debt Restructuring Member	Mar. 31, 2012 Non Accruing Troubled Debt Restructuring Member	Mar. 31, 2011 Non Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Non Accruing Troubled Debt Restructuring Member	Dec. 31, 2010 Non Accruing Troubled Debt Restructuring Member
No. of Loans		5	4			9	2			2	1		16	7
Pre-Modification Recorded Investment		$ 1,988	$ 14,862			$ 26,693	$ 1,930			$ 1,587	$ 591		$ 30,268	$ 17,383
Post-Modification Recorded Investment		1,988	14,862			23,375	1,929			1,587	501		26,950	17,292			143,233	120,016	135,327	136,800	21,543	43,130	50,870	28,147
Charge-Off	495,000,000							3,318	1			90			3,318	91					4,018	1,104
Specific Reserve				$ 68	$ 5			$ 268	$ 1			$ 93			$ 336	$ 99