Amount of cash inflow before closing and debt issuance costs received by a seller-lessee in a sale-leaseback recognized in financing activities.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 51
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51840-112757

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51831-112757

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 55
-Paragraph 52
-URI http://asc.fasb.org/extlink&oid=82846721&loc=d3e51843-112757

Name:	us-gaap_SaleLeasebackTransactionGrossProceedsFinancingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Long-Term Debt Long-Term Debt sale-leaseback (Details) $ in Thousands	1 Months Ended			9 Months Ended		12 Months Ended
	May 31, 2019 vessel	Nov. 30, 2018 vessel	Sep. 30, 2018 vessel	Sep. 30, 2019 USD ($) vessel	Sep. 30, 2018 USD ($)	Dec. 31, 2018 vessel
Debt Instrument [Line Items]
Proceeds from financing related to sales and leaseback of vessels (note 8) \| $				$ 63,720	$ 156,644
Number Of Vessels				3		8
Finance Lease Obligations [Member] \| May 2019 Sale Leaseback [Member]
Debt Instrument [Line Items]
Number Of Vessels	2
Finance Lease Obligations [Member] \| September 2018 Sale Leaseback [Member]
Debt Instrument [Line Items]
Number Of Vessels			6
Finance Lease Obligations [Member] \| November 2018 Sale leaseback Transaction [Member]
Debt Instrument [Line Items]
Number Of Vessels		4