Leases - Additional information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) Counterparty	Jan. 01, 2019 USD ($)
Operating Leased Assets [Line Items]
Number of lease agreements | Counterparty			3
Operating lease right-of-use assets (Note 16)	$ 0		$ 145,813	$ 194,000
Operating lease, liability			64,585	119,000
Other	(129,312)		(33,400)
Other current liabilities	184,229		168,323
Lease not yet commenced			705,000
Operating lease, expense	18,000	$ 18,000
Accounting Standards Update 2016-02
Operating Leased Assets [Line Items]
Other				85,000
Other current liabilities				$ (10,000)
Purchased Power Lease Contracts
Operating Leased Assets [Line Items]
Operating lease, liability			$ 0
Operating lease, expense	47,000	60,000
Contingent rentals	$ 109,000	$ 100,000