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DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ / shares in Units, $ in Thousands |  |  | 3 Months Ended | 12 Months Ended |  |  |  |
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Sep. 12, 2012 | Jul. 31, 2012 | Dec. 31, 2015 USD ($) $ / shares | Sep. 30, 2015 USD ($) $ / shares | Jun. 30, 2015 USD ($) $ / shares | Mar. 31, 2015 USD ($) $ / shares | [1] | Dec. 31, 2014 USD ($) $ / shares | [2] | Sep. 30, 2014 USD ($) $ / shares | Jun. 30, 2014 USD ($) $ / shares | Mar. 31, 2014 USD ($) $ / shares | Dec. 31, 2015 USD ($) Segment $ / shares shares | Dec. 31, 2014 USD ($) $ / shares shares | Dec. 31, 2013 USD ($) $ / shares shares | Jul. 25, 2014 | Jun. 19, 2014 | Aug. 20, 2013 | Mar. 29, 2013
DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of reportable segments | Segment |  |  |  |  |  |  |  |  |  |  | 3 |  |  |  |  |  |
Effects of Foreign Currency [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net currency exchange gains |  |  |  |  |  |  |  |  |  |  | $ 5,100 | $ 4,300 |  |  |  |  |
Net currency exchange losses |  |  |  |  |  |  |  |  |  |  |  |  | $ (600) |  |  |  |
Numerator [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net earnings |  |  | $ 2,895 | $ 4,920 | $ 6,062 | $ 5,320 | $ 1,774 | $ 1,261 | $ 3,065 | $ 2,503 | 19,197 | 8,603 | 15,908 |  |  |  |
Undistributed earnings |  |  |  |  |  |  |  |  |  |  | 15,962 | 5,416 | 12,810 |  |  |  |
Undistributed earnings allocation - basic and diluted [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Undistributed earnings |  |  |  |  |  |  |  |  |  |  | 15,962 | 5,416 | 12,810 |  |  |  |
Net earnings allocation - basic and diluted [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net earnings |  |  | $ 2,895 | $ 4,920 | $ 6,062 | $ 5,320 | $ 1,774 | $ 1,261 | $ 3,065 | $ 2,503 | 19,197 | 8,603 | 15,908 |  |  |  |
Research and Development ("R&D") [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Research and development costs |  |  |  |  |  |  |  |  |  |  | $ 27,700 | 21,500 | 14,100 |  |  |  |
Machinery and Equipment [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depreciation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |
Machinery and Equipment [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depreciation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  |  |  |  |  |  |  | 15 years |  |  |  |  |  |
Buildings and Leasehold Improvements [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depreciation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |
Buildings and Leasehold Improvements [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Depreciation [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  |  |  |  |  |  |  | 39 years |  |  |  |  |  |
Class A [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Numerator [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net earnings |  |  |  |  |  |  |  |  |  |  | $ 3,331 | 1,492 | 2,868 |  |  |  |
Less dividends declared |  |  |  |  |  |  |  |  |  |  | 522 | 522 | 522 |  |  |  |
Undistributed earnings |  |  |  |  |  |  |  |  |  |  | 2,809 | 970 | 2,346 |  |  |  |
Undistributed earnings allocation - basic and diluted [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Undistributed earnings |  |  |  |  |  |  |  |  |  |  | 2,809 | 970 | 2,346 |  |  |  |
Net earnings allocation - basic and diluted [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net earnings |  |  |  |  |  |  |  |  |  |  | $ 3,331 | $ 1,492 | $ 2,868 |  |  |  |
Weighted average shares outstanding [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average shares outstanding (in shares) | shares |  |  |  |  |  |  |  |  |  |  | 2,175 | 2,175 | 2,175 |  |  |  |
Net earnings per share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common share - basic and diluted (in dollars per share) | $ / shares |  |  | $ 0.23 | $ 0.39 | $ 0.49 | $ 0.43 | $ 0.14 | $ 0.10 | $ 0.25 | $ 0.20 | $ 1.53 | $ 0.69 | $ 1.32 |  |  |  |
Class B [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend rate Class B common stock in excess of dividend rate of Class A common stock |  |  |  |  |  |  |  |  |  |  | 5.00% | 5.00% | 5.00% |  |  |  |
Undistributed earning allocation rate of Class B common stock in excess of Class A common stock, percentage |  |  |  |  |  |  |  |  |  |  | 5.00% | 5.00% | 5.00% |  |  |  |
Numerator [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net earnings |  |  |  |  |  |  |  |  |  |  | $ 15,866 | $ 7,111 | $ 13,040 |  |  |  |
Less dividends declared |  |  |  |  |  |  |  |  |  |  | 2,713 | 2,665 | 2,576 |  |  |  |
Undistributed earnings |  |  |  |  |  |  |  |  |  |  | 13,153 | 4,446 | 10,464 |  |  |  |
Undistributed earnings allocation - basic and diluted [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Undistributed earnings |  |  |  |  |  |  |  |  |  |  | 13,153 | 4,446 | 10,464 |  |  |  |
Net earnings allocation - basic and diluted [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net earnings |  |  |  |  |  |  |  |  |  |  | $ 15,866 | $ 7,111 | $ 13,040 |  |  |  |
Weighted average shares outstanding [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average shares outstanding (in shares) | shares |  |  |  |  |  |  |  |  |  |  | 9,698 | 9,491 | 9,240 |  |  |  |
Net earnings per share [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common share - basic and diluted (in dollars per share) | $ / shares |  |  | $ 0.25 | $ 0.42 | $ 0.52 | $ 0.45 | $ 0.15 | $ 0.11 | $ 0.27 | $ 0.22 | $ 1.64 | $ 0.75 | $ 1.41 |  |  |  |
Powerbox [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition date | Sep. 12, 2012 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition of issued and outstanding capital stock, percentage | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fibreco [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition date |  | Jul. 31, 2012 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition of issued and outstanding capital stock, percentage |  | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Array [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition date |  |  |  |  |  |  |  |  |  |  | Aug. 20, 2013 |  |  |  |  |  |
Acquisition of issued and outstanding capital stock, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |
TRP [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition date |  |  |  |  |  |  |  |  |  |  | Mar. 29, 2013 |  |  |  |  |  |
Acquisition of issued and outstanding capital stock, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00%
Power Solutions [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition date |  |  |  |  |  |  |  |  |  |  | Jun. 19, 2014 |  |  |  |  |  |
Acquisition of issued and outstanding capital stock, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |
Emerson [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Acquisition date |  |  |  |  |  |  |  |  |  |  | Jul. 25, 2014 |  |  |  |  |  |
Acquisition of issued and outstanding capital stock, percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |
[1] | Revised from 10-Q disclosures to reflect immaterial measurement period adjustments related to the 2014 Acquisitions. First quarter 10-Q reflected cost of sales of $114.9 million, net earnings of $5.6 million, earnings per Class A common share of $0.45 per share and earnings per Class B common share of $0.48 per share.
[2] | Revised from the disclosure in the Annual Report on Form 10-K for the year ended December 31, 2014 to reflect immaterial measurement period adjustments related to the 2014 Acquisitions. The 2014 10-K reflected, for the fourth quarter of 2014, cost of sales of $120.8 million, net earnings of $2.0 million, earnings per Class A common share of $0.16 per share and earnings per Class B common share of $0.17 per share.

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