Segment Reporting Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 153,604	$ 202,729	$ 512,147	$ 640,649
Gross Profit	18,919	27,890	68,955	86,471
Depreciation and Amortization Expense	4,163	4,423	12,571	13,296
Selling, General & Administrative Expenses	14,126	17,614	46,502	52,739
Operating Income	4,466	9,946	21,475	32,733
Capital Expenditures	2,546	3,373	7,787	11,038
Other Items	1,520	344	2,904	1,486
Operating Segments
Segment Reporting Information [Line Items]
Revenues	153,604	202,729	512,147	640,649
Corporate/ Other
Segment Reporting Information [Line Items]
Revenues	(1,807)	(2,671)	(6,188)	(8,745)
Gross Profit	(371)	(1,858)	(1,164)	(3,768)
Depreciation and Amortization Expense	484	751	1,812	2,181
Selling, General & Administrative Expenses	4,209	5,429	15,177	16,386
Operating Income	(4,579)	(7,287)	(16,341)	(20,154)
Capital Expenditures	290	732	867	2,883
Other Items	0	0	688	0
Global Truck & Bus
Segment Reporting Information [Line Items]
Revenues	96,036	142,888	324,666	438,139
Global Truck & Bus | Operating Segments
Segment Reporting Information [Line Items]
Revenues	95,728	142,614	323,895	437,682
Gross Profit	10,765	23,780	43,019	68,010
Depreciation and Amortization Expense	2,215	2,242	6,438	6,680
Selling, General & Administrative Expenses	5,329	7,091	17,466	21,528
Operating Income	5,144	16,394	24,679	45,589
Capital Expenditures	1,592	1,979	4,039	5,119
Other Items	1,329	344	1,704	1,486
Global Truck & Bus | Intersegment Revenues
Segment Reporting Information [Line Items]
Revenues	308	274	771	457
Global Construction & Agriculture
Segment Reporting Information [Line Items]
Revenues	59,375	62,512	193,669	211,255
Global Construction & Agriculture | Operating Segments
Segment Reporting Information [Line Items]
Revenues	57,876	60,115	188,252	202,967
Gross Profit	8,525	5,968	27,100	22,229
Depreciation and Amortization Expense	1,464	1,430	4,321	4,435
Selling, General & Administrative Expenses	4,588	5,094	13,859	14,825
Operating Income	3,901	839	13,137	7,298
Capital Expenditures	664	662	2,881	3,036
Other Items	191	0	512	0
Global Construction & Agriculture | Intersegment Revenues
Segment Reporting Information [Line Items]
Revenues	$ 1,499	$ 2,397	$ 5,417	$ 8,288