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Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

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Unrecognized cost of unvested share-based compensation awards.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Note 1 - Nature of Business and Significant Accounting Policies (Details Textual)	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($) shares	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) shares	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Oct. 01, 2017 USD ($)	Aug. 31, 2005 USD ($)
Number of Subsidiaries	4								4
Number of Non-Consolidated Subsidiaries Issuing Trust Preferred Securities									6
Cash Reserve Deposit Required and Made	$ 41,803,000				$ 42,233,000				$ 41,803,000	$ 42,233,000
Initial Direct Leasing Costs As a Percentage of Cost	5.50%								5.50%
Financing Receivable, Lines of Credit Maximum Term									1 year
Commercial Real Estate Owner Occupied, Percentage	26.00%				30.00%				26.00%	30.00%
Lending Threshold Requiring Additional Loan Review	$ 1,000,000								$ 1,000,000
Goodwill	$ 28,334,092				$ 13,110,913				28,334,092	$ 13,110,913	$ 3,222,688
Goodwill, Impaired, Accumulated Impairment Loss		$ 0
Swap Fee Income									$ 3,094,939	$ 1,708,204	$ 1,717,552
Preferred Stock, Shares Authorized \| shares	250,000				250,000				250,000	250,000	250,000
Preferred Stock, Shares Outstanding \| shares	0				0				0	0
Allocated Share-based Compensation Expense									$ 1,187,035	$ 947,174	$ 941,469
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number \| shares	354,269				385,372				354,269	385,372	405,832
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 13,200,000								$ 13,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	10,500,000								10,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value									1,055,193	$ 1,525,902	$ 480,354
Income Tax Expense (Benefit)	(2,000,105)	$ 1,921,533	$ 2,635,576	$ 2,389,446	$ 2,872,412	$ 1,858,208	$ 2,153,144	$ 2,019,023	4,946,450	8,902,787	3,669,242
Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income									304,000
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)									(1,200,000)
Employee Stock Option [Member]
Allocated Share-based Compensation Expense									554,435	424,904	393,114
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 961,972								$ 961,972
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition									1 year 335 days
In The Money Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number \| shares	495,004								495,004
Restricted Stock [Member]
Allocated Share-based Compensation Expense									$ 552,907	460,853	$ 492,410
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 1,210,425								$ 1,210,425
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition									2 years 219 days
m2 Lease Funds, LLC [Member]
Goodwill													$ 3,222,688
Business Acquisition, Percentage of Voting Interests Acquired													80.00%
Community State Bank Acquisition [Member]
Goodwill					$ 9,888,225					$ 9,888,225
Guaranty Bank and Trust Company [Member]
Goodwill	$ 15,223,179								$ 15,223,179			$ 15,223,179
Business Acquisition, Percentage of Voting Interests Acquired												100.00%
Subsidiaries [Member] \| Fixed Rate Residential Mortgage [Member]
Financing Receivable, Term										15 years
Commercial Portfolio Segment [Member]
Financing Receivable, Term Loans, Generally Maximum Term									7 years
Commercial Real Estate Portfolio Segment [Member] \| Other Non-owner Occupied Commercial Real Estate Loans [Member]
Loan and Leases Receivable, Lending Limits Percent	300.00%								300.00%
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Loan and Leases Receivable, Lending Limits Percent	100.00%								100.00%
Minimum [Member]
Residual Value Percent of Cost	3.00%								3.00%
Minimum [Member] \| Subsidiaries [Member] \| Adjustable Rate Residential Mortgage [Member]
Financing Receivable, Term									1 year
Minimum [Member] \| Commercial Portfolio Segment [Member] \| Term Loan [Member]
Financing Receivable, Term									3 years
Maximum [Member]
Residual Value Percent of Cost	25.00%								25.00%
Maximum [Member] \| Subsidiaries [Member] \| Adjustable Rate Residential Mortgage [Member]
Financing Receivable, Term									5 years
Maximum [Member] \| Special Mention [Member]
Financing Receivable, Credit Weaknesses Borrowers, Term									1 year
Maximum [Member] \| Commercial Portfolio Segment [Member] \| Term Loan [Member]
Financing Receivable, Term									5 years