Segment Reporting and Geographic Locations - Sales by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues	$ 149,966	$ 153,604	$ 178,251	$ 180,291	$ 184,692	$ 202,729	$ 217,617	$ 220,303	$ 662,112	$ 825,341	$ 839,743
Gross Profit	18,276	18,919	24,331	25,704	24,352	27,890	29,506	29,074	87,230	110,822	107,688
Depreciation and Amortization Expense									16,451	17,710	18,247
Selling, General & Administrative Expenses									60,542	71,469	72,480
Operating Income	$ 3,910	$ 4,466	$ 8,427	$ 8,580	$ 5,294	$ 9,946	$ 11,588	$ 11,198	25,383	38,026	33,693
Capital Expenditures									11,917	15,590	14,569
Other Items									4,123	2,332	2,090
Operating Segments | Global Truck & Bus
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									416,279	565,269	534,118
Gross Profit									54,665	85,702	81,430
Depreciation and Amortization Expense											8,973
Selling, General & Administrative Expenses									22,557	25,263	28,890
Operating Income									30,943	59,252	51,171
Capital Expenditures									6,384	7,579	8,055
Other Items									2,712	1,838	2,090
Operating Segments | Global Construction & Agriculture
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									254,024	271,627	317,201
Gross Profit									34,060	28,627	29,583
Depreciation and Amortization Expense											5,905
Selling, General & Administrative Expenses									18,240	20,442	21,903
Operating Income									15,680	8,044	7,533
Capital Expenditures									4,609	4,688	5,140
Other Items									723	494	0
Corporate/ Other
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									(8,191)	(11,555)	(11,576)
Gross Profit									(1,495)	(3,507)	(3,325)
Depreciation and Amortization Expense											3,369
Selling, General & Administrative Expenses									19,745	25,764	21,687
Operating Income									(21,240)	(29,270)	(25,011)
Capital Expenditures									924	3,323	1,374
Other Items									688	0	0
External Revenues
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									662,112	825,341	839,743
External Revenues | Operating Segments | Global Truck & Bus
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									415,154	564,651	533,752
External Revenues | Operating Segments | Global Construction & Agriculture
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									246,958	260,690	305,991
External Revenues | Corporate/ Other
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									0	0	0
Intersegment Revenues
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									0	0	0
Intersegment Revenues | Operating Segments | Global Truck & Bus
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									1,125	618	366
Intersegment Revenues | Operating Segments | Global Construction & Agriculture
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									7,066	10,937	11,210
Intersegment Revenues | Corporate/ Other
Schedule Of Sales Revenue By Business Segment [Line Items]
Revenues									$ (8,191)	$ (11,555)	$ (11,576)