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Note 14 - Employee Benefits (Details Textual) - USD ($) |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | ---
May 07, 2019 | May 31, 2019 | Dec. 31, 2018 | Aug. 31, 2018 | May 31, 2018 | Aug. 31, 2017 | May 31, 2017 | Aug. 31, 2016 | May 31, 2016 | May 31, 2015 | May 31, 2014 | May 31, 2013 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted |  |  |  |  |  |  |  |  |  |  |  |  | 1,133,362 |  |
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate Of Unvested Outstanding Awards |  |  |  |  |  |  |  |  |  |  |  |  | 1.25% |  |
Share-based Payment Arrangement, Expense |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,817,000 | $ 3,323,000 | $ 1,250,000
Share-based Payment Arrangement, Expense, after Tax |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,400,000 | $ 2,600,000 | $ 738,000
Allocated Share Based Compensation Expense Net Of Tax Amount Per Basic And Diluted Share |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.03 | $ 0.05 | $ 0.01
Income Tax Expense (Benefit), Total |  |  |  |  |  |  |  |  |  |  |  |  | $ 16,617,000 | $ 16,002,000 | $ (33,811,000)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance |  |  | 939,193 |  |  |  |  |  |  |  |  |  | 842,329 | 939,193 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term |  |  |  |  |  |  |  |  |  |  |  |  | 3 years 4 months 24 days |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value |  |  |  |  |  |  |  |  |  |  |  |  | $ 5,800,000 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number |  |  |  |  |  |  |  |  |  |  |  |  | 523,677 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term |  |  |  |  |  |  |  |  |  |  |  |  | 2 years 4 months 24 days |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value |  |  |  |  |  |  |  |  |  |  |  |  | $ 4,600,000 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value |  |  |  |  |  |  |  |  |  |  |  |  | 1,400,000 | $ 1,500,000 | 830,000
Proceeds from Stock Options Exercised |  |  |  |  |  |  |  |  |  |  |  |  | 1,600,000 | 938,000 | 1,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value |  |  |  |  |  |  |  |  |  |  |  |  | $ 569,000 | 547,000 | 515,000
Defined Contribution Plan, Employer Matching Contribution, Percent of Match |  |  |  |  |  |  |  |  |  |  |  |  | 35.00% |  |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay |  |  |  |  |  |  |  |  |  |  |  |  | 6.00% |  |
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |
Defined Contribution Plan, Employer Discretionary Contribution Amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 | 0 | 0
Defined Contribution Plan, Cost |  |  |  |  |  |  |  |  |  |  |  |  | 2,700,000 | 2,300,000 | 2,100,000
Retirement Savings Plan, Participants Less Than 50 Years Old [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount |  |  |  |  |  |  |  |  |  |  |  |  | 19,000 |  |
Retirement Savings Plan, Participants Over50 Years Old [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount |  |  |  |  |  |  |  |  |  |  |  |  | 25,000 |  |
Accounting Standards Update 2016-09 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income Tax Expense (Benefit), Total |  |  |  |  |  |  |  |  |  |  |  |  | $ 341,000 | 319,000 | 176,000
Performance Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  |  |  |  |  |  | 5 years | 5 years |  |
Share-based Compensation Arrangement By Share-based Payment Awards, Annual Service Vesting Percentage |  |  |  |  |  |  |  |  |  |  |  | 5.00% |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,200,000 |  |
Performance Shares [Member] | One Half of Awards Paid Immediately Upon Vesting and One Half Credited to Employees' Accounts [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted |  | 40,000 |  |  | 45,700 |  | 109,169 |  | 57,669 | 58,335 | 60,668 | 104,250 |  |  |
Share-based Compensation Arrangement By Share-based Payment Awards, Annual Service Vesting Percentage |  |  |  |  |  |  | 10.00% |  |  |  |  |  |  |  |
Performance Shares [Member] | Awards Paid to Employees Upon Vesting [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted |  | 30,000 | 2,000 | 2,000 | 28,000 | 2,000 | 43,342 | 1,667 | 21,671 | 32,500 | 18,337 |  |  |  |
Unvested Service Based Option Awards [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,400,000 |  |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition |  |  |  |  |  |  |  |  |  |  |  |  | 3 years 1 month 6 days |  |
Unvested Performance Unit Awards [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,400,000 |  |
Service Based Options [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture |  |  |  |  |  |  |  |  |  |  |  |  | $ 401,000 | $ 957,000 | $ 592,000
2015 Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized | 1,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized |  |  |  |  |  |  |  |  |  |  |  |  | 2,633,333 |  |
2015 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award Annual Percentage Of Award Which Vests |  |  |  |  |  |  |  |  |  |  |  |  | 20.00% |  |
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding |  |  |  |  |  |  |  |  |  |  |  |  | 587,672 |  |
2015 Equity Incentive Plan [Member] | Performance Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding |  |  |  |  |  |  |  |  |  |  |  |  | 247,621 |  |
2015 Equity Incentive Plan [Member] | Full Value Awards [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized | 558,334 |  |  |  |  |  |  |  |  |  |  |  |  |  |
The 2005 Stock Incentive Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant |  |  | 0 |  |  |  |  |  |  |  |  |  |  | 0 |
The 2005 Stock Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding |  |  |  |  |  |  |  |  |  |  |  |  | 254,657 |  |
The 2005 Stock Incentive Plan [Member] | Performance Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |
Minimum [Member] | 2015 Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |  |
Maximum [Member] | 2015 Equity Incentive Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |  |

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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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