Equity (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016 |
Stockholders Equity Note [Line Items] | | | | |
Balance, December 31, 2016 | | | $ 208,280 | |
Net earnings | $ 1,303 | $ 1,078 | 3,418 | $ 3,710 |
Foreign currency translation adjustments | 533 | $ (312) | 1,220 | $ 961 |
Pension liability adjustment, net of tax | | | (161) | |
Balance, June 30, 2017 | 202,809 | | 202,809 | |
Common Stock [Member] | | | | |
Stockholders Equity Note [Line Items] | | | | |
Balance, December 31, 2016 | | | 10,505 | |
Net earnings | | | 0 | |
Foreign currency translation adjustments | | | 0 | |
Pension liability adjustment, net of tax | | | 0 | |
Cash dividends declared | | | 0 | |
Cash dividends paid to noncontrolling interest | | | 0 | |
Stock options exercised | | | 17 | |
Stock-based compensation expense | | | 0 | |
Income tax benefit from stock options exercised | | | 0 | |
Shares purchased and retired | | | (248) | |
Balance, June 30, 2017 | 10,274 | | 10,274 | |
Capital in Excess of Par Value [Member] | | | | |
Stockholders Equity Note [Line Items] | | | | |
Balance, December 31, 2016 | | | 50,184 | |
Net earnings | | | 0 | |
Foreign currency translation adjustments | | | 0 | |
Pension liability adjustment, net of tax | | | 0 | |
Cash dividends declared | | | 0 | |
Cash dividends paid to noncontrolling interest | | | 0 | |
Stock options exercised | | | 421 | |
Stock-based compensation expense | | | 779 | |
Income tax benefit from stock options exercised | | | 22 | |
Shares purchased and retired | | | 0 | |
Balance, June 30, 2017 | 51,406 | | 51,406 | |
Reinvested Earnings [Member] | | | | |
Stockholders Equity Note [Line Items] | | | | |
Balance, December 31, 2016 | | | 157,468 | |
Net earnings | | | 3,474 | |
Foreign currency translation adjustments | | | 0 | |
Pension liability adjustment, net of tax | | | 0 | |
Cash dividends declared | | | (4,462) | |
Cash dividends paid to noncontrolling interest | | | 0 | |
Stock options exercised | | | 0 | |
Stock-based compensation expense | | | 0 | |
Income tax benefit from stock options exercised | | | 0 | |
Shares purchased and retired | | | (6,595) | |
Balance, June 30, 2017 | 149,885 | | 149,885 | |
Accumulated Other Comprehensive Loss [Member] | | | | |
Stockholders Equity Note [Line Items] | | | | |
Balance, December 31, 2016 | | | (16,569) | |
Net earnings | | | 0 | |
Foreign currency translation adjustments | | | 918 | |
Pension liability adjustment, net of tax | | | 161 | |
Cash dividends declared | | | 0 | |
Cash dividends paid to noncontrolling interest | | | 0 | |
Stock options exercised | | | 0 | |
Stock-based compensation expense | | | 0 | |
Income tax benefit from stock options exercised | | | 0 | |
Shares purchased and retired | | | 0 | |
Balance, June 30, 2017 | (15,490) | | (15,490) | |
Noncontrolling Interest [Member] | | | | |
Stockholders Equity Note [Line Items] | | | | |
Balance, December 31, 2016 | | | 6,692 | |
Net earnings | | | (56) | |
Foreign currency translation adjustments | | | 302 | |
Pension liability adjustment, net of tax | | | 0 | |
Cash dividends declared | | | 0 | |
Cash dividends paid to noncontrolling interest | | | (204) | |
Stock options exercised | | | 0 | |
Stock-based compensation expense | | | 0 | |
Income tax benefit from stock options exercised | | | 0 | |
Shares purchased and retired | | | 0 | |
Balance, June 30, 2017 | $ 6,734 | | $ 6,734 | |