Segment Information (Narrative) (Details)	3 Months Ended
	Mar. 31, 2017 segments drilling_rigs	Mar. 31, 2016 drilling_rigs
Segment Reporting Information [Line Items]
Number of Reportable Segments | segments	2
Drilling Services Segment [Member]
Segment Reporting Information [Line Items]
Drilling Rigs	24
Colombia [Member] | Drilling Services Segment [Member]
Segment Reporting Information [Line Items]
Drilling Rigs	8
Colombia [Member] | Drilling Services Segment [Member] | Drilling Rigs [Member]
Segment Reporting Information [Line Items]
Drilling Rigs	5	5
Colombia [Member] | Drilling Services Segment [Member] | Assets Leased From Others [Member]
Segment Reporting Information [Line Items]
Drilling Rigs	3	3
United States [Member]
Segment Reporting Information [Line Items]
Drilling Divisions	4
United States [Member] | Drilling Services Segment [Member]
Segment Reporting Information [Line Items]
Drilling Rigs	16