Investment in Other Affiliates (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Eicher -Polaris Private Limited	Dec. 31, 2012 Eicher -Polaris Private Limited	Mar. 31, 2013 Brammo, Inc.	Dec. 31, 2012 Brammo, Inc.	Mar. 31, 2013 Eicher -Polaris Private Limited	Dec. 31, 2012 Eicher -Polaris Private Limited	Mar. 31, 2013 Other affiliates	Dec. 31, 2012 Other affiliates
Investments in and Advances to Affiliates [Line Items]
Investment in affiliates			$ 999		$ 12,000	$ 12,000	$ 421	$ 817	$ 12,421	$ 12,817
Equity method investment ownership percentage				50.00%
Period for proportionate share of income (loss) to be reflected in consolidated financials			1 month
Joint venture investment			50,000
Investment maturity period			3 years
Equity in loss of other affiliates	$ (412)	$ 0	$ (412)