Note 7 - Loans (Detail) - Non-accrual Troubled Debt Restructurings (USD $)	Mar. 31, 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	2,614,000	2,633,000
Interest Deferral [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	302,000	311,000
Interest Deferral [Member] | Total [Member]
Non-Accrual TDRs	2,916,000	2,944,000
Interest Deferral [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		0
Principal Deferral [Member] | Commercial Loans Member
Non-Accrual TDRs	1,073,000	616,000
Principal Deferral [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	6,859,000	9,727,000
Principal Deferral [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	1,349,000	2,427,000
Principal Deferral [Member] | Total [Member]
Non-Accrual TDRs	9,281,000	26,349,000
Principal Deferral [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		13,579,000
Rate Reduction [Member] | Commercial Loans Member
Non-Accrual TDRs	1,397,000	1,859,000
Rate Reduction [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	1,167,000	0
Rate Reduction [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	0	449,000
Rate Reduction [Member] | Total [Member]
Non-Accrual TDRs	2,564,000	14,684,000
Rate Reduction [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		12,376,000
Rate Reduction and Forgiveness of Principal [Member] | Commercial Loans Member
Non-Accrual TDRs	1,145,000	1,506,000
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	1,145,000	1,506,000
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	5,006,000	5,076,000
Rate Reduction and Payment Deferral [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	631,000	311,000
Rate Reduction and Payment Deferral [Member] | Total [Member]
Non-Accrual TDRs	5,637,000	5,387,000
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	3,615,000	3,981,000
Total Non-Accrual TDRs [Member] | Commercial Mortgage Loans [Member]
Non-Accrual TDRs	15,646,000	17,436,000
Total Non-Accrual TDRs [Member] | Residential Mortgage Loans [Member]
Non-Accrual TDRs	2,282,000	3,498,000
Total Non-Accrual TDRs [Member] | Total [Member]
Non-Accrual TDRs	21,543,000	50,870,000
Total Non-Accrual TDRs [Member] | Real Estate Construction Loans [Member]
Non-Accrual TDRs		$ 25,955,000