Commitments and contingencies (Details) $ in Thousands, gal in Millions, MMBTU in Millions		12 Months Ended
	Feb. 07, 2020 MMBTU	Dec. 31, 2019 USD ($) MMBTU Cargo gal	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Estimated Future Cash Payments [Abstract]
Prepaid balance		$ 7,097	$ 16,170
Tangible personal property tax paid			1,033	$ 1,204
Partial rebate from legal proceeding			$ 140
Estimated refund receivable		488
LNG Inventory Purchases [Member]
Estimated Future Cash Payments [Abstract]
2020		276,904
2021		224,872
2022		0
2023		0
2024		0
Prepaid balance		$ 7,097
Number of cargoes | Cargo		25
Volume of purchase commitment | gal		875.5
Energy of purchase commitment | MMBTU		72.4
LNG Inventory Purchases [Member] | Subsequent Event [Member]
Estimated Future Cash Payments [Abstract]
Energy of purchase commitment | MMBTU	27.5
Gas Inventory Purchases [Member]
Estimated Future Cash Payments [Abstract]
2020		$ 8,714
2021		6,213
2022		6,205
2023		6,271
2024		$ 12,196
Gas Inventory Purchases [Member] | Maximum [Member]
Estimated Future Cash Payments [Abstract]
Contractual purchase commitment remaining term		5 years