Note 7 - Loans (Detail) - Non-accrual Troubled Debt Restructurings (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Interest Deferral [Member] | Commercial Loans Member
Non-Accrual TDRs	$ 0	$ 0
Interest Deferral [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	2,596	2,633
Interest Deferral [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	293	311
Interest Deferral [Member] | Total [Member]
Non-Accrual TDRs	2,889	2,944
Interest Deferral [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		0
Principal Deferral [Member] | Commercial Loans Member
Non-Accrual TDRs	585	616
Principal Deferral [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	2,471	9,727
Principal Deferral [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	1,347	2,427
Principal Deferral [Member] | Total [Member]
Non-Accrual TDRs	4,403	26,349
Principal Deferral [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		13,579
Rate Reduction [Member] | Commercial Loans Member
Non-Accrual TDRs	1,370	1,859
Rate Reduction [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	6,944	0
Rate Reduction [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	0	449
Rate Reduction [Member] | Total [Member]
Non-Accrual TDRs	8,314	14,684
Rate Reduction [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		12,376
Rate Reduction and Forgiveness of Principal [Member] | Commercial Loans Member
Non-Accrual TDRs	1,145	1,506
Rate Reduction and Forgiveness of Principal [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	0	0
Rate Reduction and Forgiveness of Principal [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	0	0
Rate Reduction and Forgiveness of Principal [Member] | Total [Member]
Non-Accrual TDRs	1,145	1,506
Rate Reduction and Forgiveness of Principal [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		0
Rate Reduction and Payment Deferral [Member] | Commercial Loans Member
Non-Accrual TDRs	0	0
Rate Reduction and Payment Deferral [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	6,238	5,076
Rate Reduction and Payment Deferral [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	296	311
Rate Reduction and Payment Deferral [Member] | Total [Member]
Non-Accrual TDRs	6,534	5,387
Rate Reduction and Payment Deferral [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		0
Total Non-Accrual TDRs [Member] | Commercial Loans Member
Non-Accrual TDRs	3,100	3,981
Total Non-Accrual TDRs [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	18,249	17,436
Total Non-Accrual TDRs [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	1,936	3,498
Total Non-Accrual TDRs [Member] | Total [Member]
Non-Accrual TDRs	23,285	50,870
Total Non-Accrual TDRs [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		$ 25,955