Note 20 - Fair Value Measurement - Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale Securities	$ 192,606,119	$ 248,294,725
Securities available for sale:
Available-for-sale Securities	192,606,119	248,294,725
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	16,995,000	31,385,000
Total		31,385,000
Securities available for sale:
Available-for-sale Securities	16,995,000	31,385,000
Total		31,385,000
Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	175,611,000	216,910,000
Total		236,095,000
Securities available for sale:
Available-for-sale Securities	175,611,000	216,910,000
Total		236,095,000
Fair Value, Inputs, Level 3 [Member]
Total		0
Securities available for sale:
Total		0
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member]
Interest rate swap	121,000
Securities available for sale:
Interest rate swap	121,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Mortgage loans held for sale	0	0
Bank-owned life insurance	0	0
Total	16,995,000
Securities available for sale:
Mortgage loans held for sale	0	0
Bank-owned life insurance	0	0
Total	16,995,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member]
Interest rate swap	0	0
Securities available for sale:
Interest rate swap	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Mortgage loans held for sale	5,099,000	3,944,000
Bank-owned life insurance	18,080,000	15,635,000
Total	198,911,000
Securities available for sale:
Mortgage loans held for sale	5,099,000	3,944,000
Bank-owned life insurance	18,080,000	15,635,000
Total	198,911,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Interest rate swap	121,000	(394,000)
Securities available for sale:
Interest rate swap	121,000	(394,000)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Mortgage loans held for sale	0	0
Bank-owned life insurance	0	0
Total	0
Securities available for sale:
Mortgage loans held for sale	0	0
Bank-owned life insurance	0	0
Total	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member]
Interest rate swap	0	0
Securities available for sale:
Interest rate swap	0	0
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Mortgage loans held for sale	5,099,000	3,944,000
Bank-owned life insurance	18,080,000	15,635,000
Total	215,906,000	267,480,000
Securities available for sale:
Mortgage loans held for sale	5,099,000	3,944,000
Bank-owned life insurance	18,080,000	15,635,000
Total	215,906,000	267,480,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Interest Rate Swap [Member]
Interest rate swap		(394,000)
Securities available for sale:
Interest rate swap		(394,000)
US Government Agencies Debt Securities [Member]
Available-for-sale Securities	16,995,000	31,385,000
Securities available for sale:
Available-for-sale Securities	16,995,000	31,385,000
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities	16,995,000
Securities available for sale:
Available-for-sale Securities	16,995,000
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	16,995,000	31,385,000
Securities available for sale:
Available-for-sale Securities	16,995,000	31,385,000
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
US Government Agencies Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale Securities		31,385,000
Securities available for sale:
Available-for-sale Securities		31,385,000
Collateralized Mortgage Backed Securities [Member]
Available-for-sale Securities	95,116,000	131,684,000
Securities available for sale:
Available-for-sale Securities	95,116,000	131,684,000
Collateralized Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities	95,116,000
Securities available for sale:
Available-for-sale Securities	95,116,000
Collateralized Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
Collateralized Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	95,116,000	131,684,000
Securities available for sale:
Available-for-sale Securities	95,116,000	131,684,000
Collateralized Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
Collateralized Mortgage Backed Securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale Securities		131,684,000
Securities available for sale:
Available-for-sale Securities		131,684,000
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities	53,682,000	56,831,000
Securities available for sale:
Available-for-sale Securities	53,682,000	56,831,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities	53,682,000
Securities available for sale:
Available-for-sale Securities	53,682,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	53,682,000	56,831,000
Securities available for sale:
Available-for-sale Securities	53,682,000	56,831,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale Securities		56,831,000
Securities available for sale:
Available-for-sale Securities		56,831,000
Corporate Debt Securities [Member]
Available-for-sale Securities	26,813,000	28,395,000
Securities available for sale:
Available-for-sale Securities	26,813,000	28,395,000
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Available-for-sale Securities	26,813,000
Securities available for sale:
Available-for-sale Securities	26,813,000
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	0	0
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	26,813,000	28,395,000
Securities available for sale:
Available-for-sale Securities	26,813,000	28,395,000
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	0	0
Securities available for sale:
Available-for-sale Securities	$ 0	0
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale Securities		28,395,000
Securities available for sale:
Available-for-sale Securities		$ 28,395,000