Revenue from Contracts with Customers - Contract Liabilities Table (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 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	15,213
Revenues recognized that were included in the contract liability balance at the beginning of the period	(9,279)
Balance at March 31, 2019	151,558
Contract liabilities at March 31, 2019
Accrued liabilities		$ 6,364	$ 16,235
Other liabilities		145,194
Total contract liabilities from contracts with customers	$ 145,624	$ 151,558	$ 145,624