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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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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Name:	us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Cash, cash equivalents, and restricted cash (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 189,681	$ 234,181
Restricted cash	53,008	37,949
Cash, cash equivalents, and restricted cash	242,689	272,130	$ 277,186	$ 141,366
Funds held in trust under the terms of certain secured notes payable
Cash and Cash Equivalents [Line Items]
Restricted cash	24,331	22,681
Funds held in escrow related to construction projects and investing activities
Cash and Cash Equivalents [Line Items]
Restricted cash	23,252	10,558
Other restricted cash
Cash and Cash Equivalents [Line Items]
Restricted cash	$ 5,425	$ 4,710