Statement Of Cash Flow Information - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Restricted cash	$ 42,127	$ 54,130
Non-cash capital additions	$ 1,600	$ 10,200

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