Condensed Consolidated Statements of Cash Flows (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Reconciliation of cash, cash equivalents and restricted cash and cash equivalents to the condensed consolidated balance sheets
Cash and cash equivalents	$ 329,515	$ 263,229
Restricted cash and cash equivalents	172,506	72,430
Restricted cash, included in prepaid expenses and other current assets	1,897
Total cash, cash equivalents and restricted cash and cash equivalents	$ 503,918	$ 335,659

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