Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Statement of Cash Flows [Abstract]
Cash	$ 694	$ 3,657	$ 2,799	$ 5,230
Restricted cash	41,803	46,484	26,356	16,787
Total cash and restricted cash	$ 42,497	$ 50,141	$ 29,155	$ 22,017

Amount of cash and cash equivalents restricted as to withdrawal or usage. 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