Gain on other sales (Details Textual) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Gain on other sales disclosure [Line Items]
Gain (Loss) On Other Sales	$ 877	$ 1,132		$ 3,248	$ 10,267
Gain On Sale Of Idle Use Right And Plant Before Tax			$ 7,500
Net Book Value Of Land Use Right And Plant			900
Selling Price Of Land Use Right And Plant			$ 8,400
Gain Loss On Other Sales Period Decrease				$ 7,100