Accrued expenses and other payables (Details 1) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Accrued Expenses [Line Items]
Balance at the beginning of year	$ 25,011	$ 22,104	$ 22,104
Additions during the period	4,419	5,055	12,341
Settlement within period, by cash or actual material	(3,448)	(2,972)	(9,354)
Foreign currency translation gain (loss)	22	(201)	(80)
Balance at end of year	$ 26,004	$ 23,986	$ 25,011