Note 2 - Acquisitions (Details Textual) - USD ($) $ in Thousands | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2017 | Sep. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2017 | Jun. 30, 2018 |
Payments to Acquire Businesses, Net of Cash Acquired | | | | | | | | | $ 10,397 | $ 24,660 | | |
Goodwill | | | $ 242,690 | | $ 249,685 | | | | 249,685 | | $ 249,685 | |
Business Combination, Acquisition Related Costs | | | | | | | | $ 800 | 303 | 800 | | |
Amortization of Intangible Assets | | | | | 2,300 | | | 1,100 | 4,500 | 2,000 | | |
Interest Expense | | | | | 1,793 | | | 850 | 3,514 | 1,547 | | |
Business Combination, Contingent Consideration, Liability | [1] | | 2,108 | | 3,513 | | | | 3,513 | | 3,513 | |
Business Combination, Deferred Compensation Arrangements | | | | | 703 | | | 703 | 1,405 | 703 | | |
Piazza Rosa Group [Member] | | | | | | | | | | | | |
Payments to Acquire Businesses, Net of Cash Acquired | | $ 10,056 | | | 10,056 | $ 10,100 | | | | | | |
Other Payments to Acquire Businesses | | 2,833 | | | 2,833 | 2,800 | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | 4,087 | | | 4,086 | 4,087 | | | 4,086 | | 4,086 | |
Goodwill, Purchase Accounting Adjustments | | | | | 1,155 | | | | | | | |
Goodwill | | 6,218 | | | 5,063 | 6,218 | | | 5,063 | | 5,063 | |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles | | | | | 1 | | | | | | | |
Piazza Rosa Group [Member] | Trademarks (Indefinite-Lived) [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | 1,600 | | | | 1,600 | | | | | | |
Piazza Rosa Group [Member] | Customer Relationships [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | 2,300 | | | | $ 2,300 | | | | | | |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life | | | | | | 8 years | | | | | | |
Piazza Rosa Group [Member] | Other Intangible Assets [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | $ 200 | | | | $ 200 | | | | | | |
Standex Electronics Japan Corporation [Member] | | | | | | | | | | | | |
Payments to Acquire Businesses, Net of Cash Acquired | | | | $ 129,155 | | | $ 129,200 | | 129,155 | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | | | 53,800 | 51,400 | | 53,800 | | 51,400 | | 51,400 | |
Goodwill, Purchase Accounting Adjustments | | | | | | | | | | | 3,202 | |
Goodwill | | | | $ 75,985 | 79,187 | | $ 75,985 | | 79,187 | | 79,187 | |
Business Acquisition, Percentage of Voting Interests Acquired | | | | 100.00% | | | 100.00% | | | | | |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Pension | | | | | | | | | | | 1,900 | |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles | | | | | | | | | | | $ (2,400) | |
Standex Electronics Japan Corporation [Member] | Acquisition-related Costs [Member] | | | | | | | | | | | | |
Business Combination, Acquisition Related Costs | | | | | 200 | | | | | | | |
Standex Electronics Japan Corporation [Member] | Fair Value Adjustment to Intangible Assets [Member] | | | | | | | | | | | | |
Business Combination, Acquisition Related Costs | | | | | | | | | | 200 | | |
Amortization of Intangible Assets | | | | | | | | 700 | | 1,400 | | |
Interest Expense | | | | | | | | | | 700 | | |
Standex Electronics Japan Corporation [Member] | Fair Value Adjustment to Fixed Assets [Member] | | | | | | | | | | | | |
Depreciation | | | | | | | | 300 | | 600 | | |
Standex Electronics Japan Corporation [Member] | Fair Value Adjustment to Credit Facility [Member] | | | | | | | | | | | | |
Business Combination, Acquisition Related Costs | | | | | | | | 200 | | | | |
Interest Expense | | | | | | | | 400 | | | | |
Standex Electronics Japan Corporation [Member] | Customer Relationships [Member] | | | | | | | | | | | | |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life | | | | | | | | | | | 15 years | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles | | | | | 3,400 | | | | 3,400 | | $ 3,400 | |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles | | | | | | | | | | | (200) | |
Standex Electronics Japan Corporation [Member] | Developed Technology Rights [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles | | | | | 47,800 | | | | 47,800 | | 47,800 | |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles | | | | | | | | | | | $ (2,300) | |
Standex Electronics Japan Corporation [Member] | Developed Technology Rights [Member] | Minimum [Member] | | | | | | | | | | | | |
Finite-Lived Intangible Asset, Useful Life | | | | | | | | | | | 10 years | |
Standex Electronics Japan Corporation [Member] | Developed Technology Rights [Member] | Maximum [Member] | | | | | | | | | | | | |
Finite-Lived Intangible Asset, Useful Life | | | | | | | | | | | 20 years | |
Standex Electronics Japan Corporation [Member] | Order or Production Backlog [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles | | | | | 200 | | | | 200 | | $ 200 | |
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles | | | | | | | | | | | $ 100 | |
Horizon Scientific Inc. [Member] | | | | | | | | | | | | |
Payments to Acquire Businesses, Net of Cash Acquired | | | 25,001 | | | | | 25,000 | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | | 16,150 | | | | | $ 16,200 | | $ 16,200 | | |
Goodwill | | | $ 6,660 | | | | | | | | | |
Business Acquisition, Percentage of Voting Interests Acquired | | | | | | | | 100.00% | | 100.00% | | |
Business Combination, Contingent Consideration, Liability | | | | | | | | $ 8,400 | | $ 8,400 | | |
Business Combination, Deferred Compensation Due on Second Anniversary | | | | | | | | 2,800 | | 2,800 | | |
Business Combination, Deferred Compensation Due on Third Anniversary | | | | | | | | 5,600 | | 5,600 | | |
Business Combination, Deferred Compensation Arrangements | | | | | $ 700 | | | | $ 1,400 | | | |
Horizon Scientific Inc. [Member] | Scenario, Forecast [Member] | | | | | | | | | | | | |
Payments for Previous Acquisition | | | | | | | | | | | | $ 300 |
Horizon Scientific Inc. [Member] | Customer Relationships [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | | | | | | | $ 14,500 | | 14,500 | | |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life | | | | | | | | 15 years | | | | |
Horizon Scientific Inc. [Member] | Order or Production Backlog [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles | | | | | | | | $ 300 | | 300 | | |
Horizon Scientific Inc. [Member] | Trademarks [Member] | | | | | | | | | | | | |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill | | | | | | | | $ 1,400 | | $ 1,400 | | |
| |
[1] | The fair value of our contingent consideration arrangement is determined based on our evaluation as to the probability and amount of any deferred compensation that has been earned to date. | |