Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stockholders Equity Note [Line Items]
Balance, December 31, 2014			$ 197,954
Net earnings	$ 2,085	$ 2,501	5,677	$ 5,751
Foreign currency translation adjustments	97	$ 546	(1,500)	$ 630
Pension liability adjustment, net of tax			543
Balance, June 30, 2015	199,706		199,706
Common Stock [Member]
Stockholders Equity Note [Line Items]
Balance, December 31, 2014			10,821
Net earnings			0
Foreign currency translation adjustments			0
Pension liability adjustment, net of tax			0
Cash dividends declared			0
Stock options exercised			130
Stock-based compensation expense			0
Income tax benefit from stock options exercised			0
Shares purchased and retired			(85)
Balance, June 30, 2015	10,866		10,866
Capital in Excess of Par Value [Member]
Stockholders Equity Note [Line Items]
Balance, December 31, 2014			37,966
Net earnings			0
Foreign currency translation adjustments			0
Pension liability adjustment, net of tax			0
Cash dividends declared			0
Stock options exercised			2,382
Stock-based compensation expense			721
Income tax benefit from stock options exercised			451
Shares purchased and retired			0
Balance, June 30, 2015	41,520		41,520
Reinvested Earnings [Member]
Stockholders Equity Note [Line Items]
Balance, December 31, 2014			160,179
Net earnings			5,673
Foreign currency translation adjustments			0
Pension liability adjustment, net of tax			0
Cash dividends declared			(4,231)
Stock options exercised			0
Stock-based compensation expense			0
Income tax benefit from stock options exercised			0
Shares purchased and retired			(2,336)
Balance, June 30, 2015	159,285		159,285
Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders Equity Note [Line Items]
Balance, December 31, 2014			(18,030)
Net earnings			0
Foreign currency translation adjustments			(1,212)
Pension liability adjustment, net of tax			543
Cash dividends declared			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, 2015	(18,699)		(18,699)
Noncontrolling Interest [Member]
Stockholders Equity Note [Line Items]
Balance, December 31, 2014			7,018
Net earnings			4
Foreign currency translation adjustments			(288)
Pension liability adjustment, net of tax			0
Cash dividends declared			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, 2015	$ 6,734		$ 6,734