Industry Segments - Schedule of reporting information by segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net Sales	$ 158,271	$ 162,109	$ 152,784	$ 150,485	$ 144,724	$ 141,442	$ 153,623	$ 144,944	$ 623,649	$ 584,733	$ 545,572
Income from Continuing Operations Before Income Taxes									22,618	44,316	46,526
Interest expense - net									(8,535)	(4,531)	(4,330)
Income from continuing operations before income taxes									14,083	39,785	42,196
Identifiable Assets	564,833				469,457				564,833	469,457	484,856
Capital Additions, Net									24,170	20,709	19,861
Depreciation and Amortization									31,172	23,528	19,476
Operating Segments [Member]
Segment Reporting Information [Line Items]
Interest expense - net									(8,535)	(4,531)	(4,330)
Operating Segments [Member] | Material Handling [Member]
Segment Reporting Information [Line Items]
Net Sales									432,054	380,605	337,474
Income from Continuing Operations Before Income Taxes									31,903	47,428	51,296
Capital Additions, Net									22,197	18,787	18,199
Depreciation and Amortization									29,013	21,728	18,034
Operating Segments [Member] | Distribution [Member]
Segment Reporting Information [Line Items]
Net Sales									191,873	204,460	208,567
Income from Continuing Operations Before Income Taxes									16,024	21,727	22,582
Capital Additions, Net									1,786	915	1,086
Depreciation and Amortization									1,022	859	786
Operating Segments [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Income from Continuing Operations Before Income Taxes									(25,309)	(24,839)	(27,352)
Capital Additions, Net									187	1,007	576
Depreciation and Amortization									1,137	941	656
Operating Segments [Member] | Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	117,775				160,568				117,775	160,568	166,221
Operating Segments [Member] | Continuing Operations [Member] | Material Handling [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	370,501				240,897				370,501	240,897	254,165
Operating Segments [Member] | Continuing Operations [Member] | Distribution [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	57,523				63,340				57,523	63,340	56,674
Operating Segments [Member] | Continuing Operations [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	19,034				4,652				19,034	4,652	7,796
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net Sales									$ (278)	$ (332)	$ (469)