CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Restricted cash	$ 31,634	$ 11,789	$ 12,217	$ 6,192
Variable Interest Entity, Primary Beneficiary [Member]
Cash	23,779	20,685	22,445	30,449
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Cash	$ 14,550	$ 14,735	$ 12,508	$ 15,685

Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as noncurrent. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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