Segment Information (Schedule Of Geographic Distribution Of Rigs By Segment) (Details)	Dec. 31, 2018 rigs
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	59
Floaters [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	24
Jackups [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	35
North & South America (Excluding Brazil) [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	12
North & South America (Excluding Brazil) [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	8
North & South America (Excluding Brazil) [Member] | Jackups [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	4
Europe & Mediterranean [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	18
Europe & Mediterranean [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	7
Europe & Mediterranean [Member] | Jackups [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	11
Middle East & Africa [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	15
Middle East & Africa [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	3
Middle East & Africa [Member] | Jackups [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	12
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	11
Asia Pacific [Member] | Construction in Progress [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	3
Asia Pacific [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	4
Asia Pacific [Member] | Floaters [Member] | Construction in Progress [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	2
Asia Pacific [Member] | Jackups [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	7
Asia Pacific [Member] | Jackups [Member] | Construction in Progress [Member]
Segment Reporting Information [Line Items]
Total number of contract drilling rigs	1