Note 7 - Loans (Detail) - Troubled Debt Restructurings Modified (USD $) In Thousands, unless otherwise specified			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Commercial Loans Member Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Commercial Loans Member Accruing Troubled Debt Restructuring Member	Sep. 30, 2012 Commercial Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Commercial Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Sep. 30, 2012 Residential Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Residential Mortgage Loans [Member] Accruing Troubled Debt Restructuring Member	Sep. 30, 2012 Total [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Total [Member] Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Real Estate Construction Loans [Member] Accruing Troubled Debt Restructuring Member	Sep. 30, 2012 Accruing Troubled Debt Restructuring Member	Sep. 30, 2011 Accruing Troubled Debt Restructuring Member	Sep. 30, 2012 Accruing Troubled Debt Restructuring Member	Sep. 30, 2011 Accruing Troubled Debt Restructuring Member	Jun. 30, 2012 Accruing Troubled Debt Restructuring Member	Dec. 31, 2011 Accruing Troubled Debt Restructuring Member	Jun. 30, 2011 Accruing Troubled Debt Restructuring Member	Dec. 31, 2010 Accruing Troubled Debt Restructuring Member
No. of Loans			8	11	15	3	7	3	30	19	2
Pre-Modification Recorded Investment			$ 2,144	$ 39,584	$ 59,299	$ 3,176	$ 2,895	$ 1,577	$ 64,338	$ 70,512	$ 26,175
Post-Modification Recorded Investment			2,144	39,584	55,610	3,176	2,895	1,577	60,649	69,654	25,317	170,151	126,270	170,151	126,270	153,249	120,016	116,328	136,800
Charge-Off			0	0	3,689	0	0	0	3,689	858	858	(251)	(1)	(251)	(660)
Specific Reserve	$ 5,425	$ 7,554	$ 75	$ 112	$ 0	$ 1	$ 70	$ 116	$ 145	$ 229