Restricted Net Assets (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Restricted Net Assets (Textual)
Company's restricted net assets	$ 50,873,000	$ 57,324,000
Annual appropriations required by statutory reserve fund, description	At least 10% of after-tax profit, if any, of the relevant PRC VIEs and subsidiary.

Total assets that cannot be used for operating purposes because of contract or regulatory requirements that are in effect for a period that extends beyond one year.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_OtherRestrictedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant