Interest on deferred compensation amounts.

No definition available.

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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

No definition available.

+ Details

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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.

+ Details

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(ii)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e2709-114920

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(5)(iv)(01)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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Note 14 - Employee Benefit Plans (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	4.50%
Defined Contribution Plan, Cost	$ 400,784	$ 322,575	$ 297,826
Deferred Compensation Liability, Current and Noncurrent	12,346,935	10,455,183	8,875,025	$ 7,503,692
Deferred Compensation Arrangement with Individual, Contributions by Employer	932,921	794,168	693,656
Minimum [Member] \| Certain Executive Officers [Member]
Deferred Compensation Arrangement with Individual, Contributions by Employer	$ 8,000
Interest on Deferred Compensation Amounts	4.00%
Maximum [Member] \| Certain Executive Officers [Member]
Deferred Compensation Arrangement with Individual, Contributions by Employer	$ 25,000
Interest on Deferred Compensation Amounts	12.00%
Supplemental Executive Retirement Plans [Member]
Deferred Compensation Liability, Current and Noncurrent	$ 4,330,313	4,093,355
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 163,826	163,825	$ 163,824
Certain Management Officers [Member]s [Member] \| Minimum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%
Interest on Deferred Compensation Amounts	4.00%
Certain Management Officers [Member]s [Member] \| Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	10.00%
Interest on Deferred Compensation Amounts	8.00%
Agreements with Certain Management and Executive Officers [Member]
Deferred Compensation Liability, Current and Noncurrent	$ 12,346,935	$ 10,455,183
First 3% of Employees Wages [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	100.00%
Match at 100% [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3.00%
From 4% to 4.5% of Employees Wages [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Matched at 50% [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3.00%