Revenue and Accounts Receivable - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Contract with Customer, Asset, Net, Current [Roll Forward]
Contract with Customer, Receivable, Net, Current	$ 296,355	$ 309,075
Contract with Customer, Receivable, Current, Net Increase (Decrease)	(48,910)	47,926
Contract with Customer, Receivable, Net, Current	247,445	357,001
Contract with Customer, Asset, Gross, Current	31,525	2,833
Contract with Customer, Contract Asset, Current, Net Increase (Decrease)	166	(2,833)
Contract with Customer, Asset, Gross, Current	31,691	0
Contract with Customer, Asset, Net, Noncurrent [Roll Forward]
Contract with Customer, Receivable, Net, Noncurrent	63,554	60,948
Contract with Customer, Receivable, NonCurrent, Net Increase (Decrease)	(3,968)	(152)
Contract with Customer, Receivable, Net, Noncurrent	59,586	60,796
Contract with Customer, Asset, Gross, Noncurrent	2,504	541
Increase (Decrease) in Contract Receivables, Net	6,960	2,073
Contract with Customer, Asset, Gross, Noncurrent	9,464	2,614
Contract with Customer, Liability, Current [Roll Forward]
Contract with Customer, Liability, Current	2,492	4,016
Contract with Customer, Liability, Current, Net Increase (Decrease)	3,131	2,327
Contract with Customer, Liability, Current	5,623	6,343
Contract with Customer, Liability, Noncurrent [Roll Forward]
Contract with Customer, Liability, Noncurrent	615	1,731
Contract with Customer, Liability, Noncurrent, Net Increase (Decrease)	0	0
Contract with Customer, Liability, Noncurrent	$ 615	$ 1,731