Reconciliation of Equity Attributable to the Non-controlling Interests (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of equity attributable to the non-controlling interests
Non-controlling interests at beginning of period	$ 7,309
Less: Net (loss) attributable to the non-controlling interests	1,721	$ 1,001	$ 776
Non-controlling interests at end of period	5,588	7,309
Variable Interest Entity [Member]
Reconciliation of equity attributable to the non-controlling interests
Non-controlling interests at beginning of period	7,309	8,310
Less: Net (loss) attributable to the non-controlling interests	(1,721)	(1,001)
Non-controlling interests at end of period	$ 5,588	$ 7,309	$ 8,310