Segment Information (Schedule Of Geographic Distribution Of Rigs By Segment) (Details)	Mar. 31, 2016 rigs
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	68	[1]
Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	26
Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	42
North South America Incl Brazil [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	20	[1]
North South America Incl Brazil [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	13
North South America Incl Brazil [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	7
Europe & Mediterranean [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	14	[1]
Europe & Mediterranean [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	3
Europe & Mediterranean [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	11
Middle East [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	13	[1]
Middle East [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	2
Middle East [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	11
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	11	[1]
Asia Pacific [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	4
Asia Pacific [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	7
Middle East Under Construction [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	2	[1]
Middle East Under Construction [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	0
Middle East Under Construction [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	2
Middle East Under Construction [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	6	[1]
Middle East Under Construction [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	3
Middle East Under Construction [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	3
Asia & Pacific Rim (under construction) [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	2	[1]
Asia & Pacific Rim (under construction) [Member] | Floaters [Member]
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	1
Asia & Pacific Rim (under construction) [Member] | Jackups Member
Segment Reporting Information [Line Items]
Number of contract drilling rigs (in rigs)	1

[1] We provide management services on three rigs owned by third-parties not included in the table above.