Income tax rate (Details Textual) BRL in Thousands, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended			12 Months Ended
	Jan. 31, 2008	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015 USD ($)	Sep. 30, 2015 BRL	Sep. 30, 2014	Dec. 31, 2014 USD ($)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2009
Income Tax Disclosure [Line Items]
Tax rate				35.00%	35.00%
Withholding Tax Percentage Applicable To Foreign Investors As Non Resident Enterprises	10.00%
Withholding Tax Percentage Applicable To Foreign Investors To Direct Holding Company				5.00%	5.00%
Percentage Owned In Holding Company To Avail Withholding Tax Of Five Percent				25.00%	25.00%
Undistributed Earnings, Basic				$ 201,100			$ 188,300
Tax Provision On Retained Earning Not Reinvested				$ 10,100			$ 9,400
Increase In Income Tax Expense Benefit Percentage		18.10%	14.90%	16.60%	16.60%	17.90%
Shashi Jiulong Power Steering Gears Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes							15.00%
Jingzhou Henglong Automotive Parts Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes							15.00%
Shenyang Jinbei Henglong Automotive Steering System Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes				15.00%	15.00%				15.00%		15.00%
Wuhu Henglong Automotive Steering System Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes				15.00%	15.00%			15.00%
Wuhan Jielong Electric Power Steering Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes								15.00%
Hubei Henglong Automotive System Group Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes							15.00%	15.00%
Universal Sensor Application Inc [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes				25.00%	25.00%
Hong Kong Enterprise [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes				16.50%	16.50%
Chongqing Henglong Hongyan Automotive Systems Co Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes									25.00%
CAAS Brazils Imports and Trade In Automotive Parts Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential				10.00%	10.00%
Additional Tax Payable Subject To Residential Status				$ 120
United States [Member]
Income Tax Disclosure [Line Items]
Deferred State and Local Income Tax Expense (Benefit)				170
Undistributed Earnings, Basic				$ 3,400
Fujian Qiaolong Special Purpose Vehicle Co., Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes							15.00%			15.00%
CAAS Brazils Imports and Trade In Automotive Part Ltd [Member]
Income Tax Disclosure [Line Items]
Effective Income Tax Rate Reconciliation, State and Local Income Taxes				15.00%	15.00%
Additional Tax Payable Subject To Residential Status | BRL					BRL 240