Note 4 - Loans Leases Receivable - Allowance for Estimated Losses on Loans Leases (Details) - USD ($)		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Balance					$ 34,355,728				$ 30,757,448	$ 34,355,728	$ 30,757,448	$ 26,140,906
Provision for loan/lease losses		$ 1,612,047	$ 6,205,828	$ 2,300,735	2,539,839	$ 2,255,381	$ 2,086,436	$ 2,022,993	2,105,109	12,658,449	8,469,919	7,478,166
Loans/leases charged off										(7,919,397)	(5,373,213)	(3,244,183)
Recoveries on loans/leases previously charged off										752,328	501,574	382,559
Balance		39,847,108				34,355,728				39,847,108	34,355,728	30,757,448
Allowance for impaired loans/leases													$ 3,658,545	$ 3,043,319
Allowance for nonimpaired loans/leases													36,188,563	31,312,409
Less allowance for estimated losses on loans/leases		39,847,108			34,355,728	34,355,728			30,757,448	34,355,728	30,757,448	26,140,906	39,847,108	34,355,728
Impaired loans/leases													20,202,558	18,354,163
Nonimpaired loans/leases													3,703,427,664	2,938,359,330
Loans and leases													$ 3,723,630,222	$ 2,956,713,493
Allowance as a percentage of impaired loans/leases													18.11%	16.58%
Allowance as a percentage of nonimpaired loans/leases													0.98%	1.07%
Total allowance as a percentage of total loans/leases													1.07%	1.16%
Commercial Portfolio Segment [Member]
Balance					14,323,036				12,545,110	14,323,036	12,545,110	10,484,080
Provision for loan/lease losses										7,161,066	2,736,296	2,478,912
Loans/leases charged off										(5,358,683)	(1,149,790)	(527,152)
Recoveries on loans/leases previously charged off										294,798	191,420	109,270
Balance		16,420,217				14,323,036				16,420,217	14,323,036	12,545,110
Allowance for impaired loans/leases													$ 972,647	$ 715,627
Allowance for nonimpaired loans/leases													15,447,570	13,607,409
Less allowance for estimated losses on loans/leases		16,420,217			14,323,036	14,323,036			12,545,110	14,323,036	12,545,110	10,484,080	16,420,217	14,323,036
Impaired loans/leases													4,499,451	6,248,209
Nonimpaired loans/leases													1,424,910,136	1,128,268,106
Loans and leases													$ 1,429,409,587	$ 1,134,516,315
Allowance as a percentage of impaired loans/leases													21.62%	11.45%
Allowance as a percentage of nonimpaired loans/leases													1.08%	1.21%
Total allowance as a percentage of total loans/leases													1.15%	1.26%
Commercial Real Estate Portfolio Segment [Member]
Balance					13,962,688				11,670,609	13,962,688	11,670,609	9,375,117
Provision for loan/lease losses										4,094,223	4,044,460	2,286,953
Loans/leases charged off										(387,499)	(1,795,229)	(24,304)
Recoveries on loans/leases previously charged off										49,839	42,848	32,843
Balance		17,719,251				13,962,688				17,719,251	13,962,688	11,670,609
Allowance for impaired loans/leases													$ 2,123,685	$ 1,429,460
Allowance for nonimpaired loans/leases													15,595,566	12,533,228
Less allowance for estimated losses on loans/leases		17,719,251			13,962,688	13,962,688			11,670,609	13,962,688	11,670,609	9,375,117	17,719,251	13,962,688
Impaired loans/leases													10,446,748	6,529,262
Nonimpaired loans/leases													1,755,664,027	1,296,962,620
Loans and leases													$ 1,766,110,775	$ 1,303,491,882
Allowance as a percentage of impaired loans/leases													20.33%	21.89%
Allowance as a percentage of nonimpaired loans/leases													0.89%	0.97%
Total allowance as a percentage of total loans/leases													1.00%	1.07%
Finance Leases Portfolio Segment [Member]
Balance					2,382,098				3,111,898	2,382,098	3,111,898	3,395,088
Provision for loan/lease losses										1,068,161	1,369,624	2,127,463
Loans/leases charged off										(2,002,227)	(2,284,910)	(2,503,417)
Recoveries on loans/leases previously charged off										344,454	185,486	92,764
Balance		1,792,486				2,382,098				1,792,486	2,382,098	3,111,898
Allowance for impaired loans/leases													$ 194,008	$ 504,469
Allowance for nonimpaired loans/leases													1,598,478	1,877,629
Less allowance for estimated losses on loans/leases		1,792,486			2,382,098	2,382,098			3,111,898	2,382,098	3,111,898	3,395,088	1,792,486	2,382,098
Impaired loans/leases													2,248,597	3,669,492
Nonimpaired loans/leases													115,720,085	137,778,740
Loans and leases													$ 117,968,682	$ 141,448,232
Allowance as a percentage of impaired loans/leases													8.63%	13.75%
Allowance as a percentage of nonimpaired loans/leases													1.38%	1.36%
Total allowance as a percentage of total loans/leases													1.52%	1.68%
Residential Portfolio Segment [Member]
Balance					2,466,431				2,342,344	2,466,431	2,342,344	1,790,150
Provision for loan/lease losses										193,153	197,034	628,114
Loans/leases charged off										(126,566)	(102,088)	(76,820)
Recoveries on loans/leases previously charged off										23,618	29,141	900
Balance		2,556,636				2,466,431				2,556,636	2,466,431	2,342,344
Allowance for impaired loans/leases													$ 257,014	$ 355,167
Allowance for nonimpaired loans/leases													2,299,622	2,111,264
Less allowance for estimated losses on loans/leases		2,556,636			2,466,431	2,466,431			2,342,344	2,466,431	2,342,344	1,790,150	2,556,636	2,466,431
Impaired loans/leases													2,109,612	1,704,846
Nonimpaired loans/leases													288,649,786	256,941,419
Loans and leases	[1]												$ 290,759,398	$ 258,646,265
Allowance as a percentage of impaired loans/leases													12.18%	20.83%
Allowance as a percentage of nonimpaired loans/leases													0.80%	0.82%
Total allowance as a percentage of total loans/leases													0.88%	0.95%
Consumer Portfolio Segment [Member]
Balance					1,221,475				1,087,487	1,221,475	1,087,487	1,096,471
Provision for loan/lease losses										141,846	122,505	(43,276)
Loans/leases charged off										(44,422)	(41,196)	(112,490)
Recoveries on loans/leases previously charged off										39,619	52,679	146,782
Balance		1,358,518				1,221,475				1,358,518	1,221,475	1,087,487
Allowance for impaired loans/leases													$ 111,191	$ 38,596
Allowance for nonimpaired loans/leases													1,247,327	1,182,879
Less allowance for estimated losses on loans/leases		$ 1,358,518			$ 1,221,475	$ 1,221,475			$ 1,087,487	$ 1,221,475	$ 1,087,487	$ 1,096,471	1,358,518	1,221,475
Impaired loans/leases													898,150	202,354
Nonimpaired loans/leases													118,483,630	118,408,445
Loans and leases													$ 119,381,780	$ 118,610,799
Allowance as a percentage of impaired loans/leases													12.38%	19.07%
Allowance as a percentage of nonimpaired loans/leases													1.05%	1.00%
Total allowance as a percentage of total loans/leases													1.14%	1.03%

[1] Includes residential real estate loans held for sale totaling $1.3 million and $645 thousand as of December 31, 2018 and 2017, respectively.