Note 14 - Employee Benefit Plans - Deferred Compensation Agreements (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance, beginning	$ 12,346,935	$ 10,455,183	$ 8,875,025
Employee deferrals	1,406,959	932,921	794,168
Company match and interest	1,367,776	1,024,933	848,831
Cash payments made	(92,265)	(66,102)	(62,841)
Balance, ending	15,029,405	12,346,935	10,455,183
Supplemental Executive Retirement Plans [Member]
Balance, beginning	4,330,313	4,093,355	3,934,605
Company match and interest	456,782	400,784	322,575
Cash payments made	(163,826)	(163,826)	(163,825)
Balance, ending	$ 4,623,269	$ 4,330,313	$ 4,093,355

The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 710
-SubTopic 10
-Section 30
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6409875&loc=d3e20015-108363

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- Definition

Amount of contributions made by employer into fund established for purposes of making future disbursement to individual in accordance with deferred compensation arrangement.

+ References

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- Definition

Amount of distribution made to individual in accordance with deferred compensation arrangement.

+ References

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

+ References

No definition available.

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