Revenue from Contracts with Customers Amortization of Deferred Revenues and Costs (Details) - Drilling Services [Member] - USD ($) $ in Thousands	1 Months Ended	5 Months Ended	6 Months Ended
	Jun. 30, 2020	May 31, 2020	Jun. 30, 2019
Deferred Revenue Arrangement [Line Items]
Amortization of deferred revenues	$ 46	$ 2,705	$ 2,235
Amortization of deferred costs	$ 39	$ 1,876	$ 2,096