Segment Information (Schedule of Revenues from External Customers and Long-Lived Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	$ 1,426,377	$ 1,324,257	$ 1,229,623
Revenues	239,034	229,670
Drilling Services Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	780,786	870,291
Drilling Rigs	62
Drilling Services Segment [Member] | Colombia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	153,158	151,498
Revenues	$ 22,164	$ 30,775
Drilling Rigs	8
Drilling Services Segment [Member] | Colombia [Member] | Drilling Rigs [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Drilling Rigs	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