Revenue from Contracts with Customers - Contract Liabilities Table (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Change in Contracts with Customer, Liability [Roll Forward]
Balance at December 31, 2018	$ 145,624
Cash received or receivable, excluding revenues recognized during the period	28,588
Revenues recognized that were included in the contract liability balance at the beginning of the period	(10,183)
Balance at June 30, 2019	164,029
Contract liabilities at June 30, 2019
Accrued liabilities		$ 6,620	$ 16,235
Other liabilities		157,409
Total contract liabilities from contracts with customers	$ 145,624	$ 164,029	$ 145,624