Segment Information (Schedule of Revenues from External Customers and Long-Lived Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	$ 1,251,431	$ 1,291,533	$ 1,251,431	$ 1,291,533	$ 1,229,623
Revenues	259,812	248,354	498,846	478,024
Drilling Services Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	778,148	849,649	778,148	849,649
Drilling Rigs	62		62
Drilling Services Segment [Member] | Colombia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	157,025	150,223	157,025	150,223
Revenues	$ 25,527	$ 30,627	$ 47,691	$ 61,402
Drilling Rigs	8		8
Drilling Services Segment [Member] | Colombia [Member] | Drilling Rigs [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling Rigs	5		5		5
Drilling Services Segment [Member] | Colombia [Member] | Assets Leased From Others [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling Rigs	3		3		3