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Note 19 - Stock Repurchase Program (Details Textual) - USD ($) shares in Thousands, $ in Millions | 9 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2018 | Dec. 31, 2017 | Feb. 01, 2016
Treasury Stock, Shares, Acquired | 0 | 0 |
February 2016 Repurchase Program [Member] |  |  |
Stock Repurchase Program, Authorized Amount |  |  | $ 45.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount | $ 7.5 | $ 7.5 |

X
- Definition Amount of stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Amount remaining of a stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |