Segment Information (Schedule of Revenues from External Customers and Long-Lived Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	$ 1,264,757	$ 1,251,601	$ 1,264,757	$ 1,251,601	$ 1,229,623
Revenues	273,267	243,979	772,113	722,003
Drilling Services Segment [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	789,103	818,161	789,103	818,161
Drilling Rigs	62		62
Drilling Services Segment [Member] | Colombia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Identifiable assets	150,287	153,287	150,287	153,287
Revenues	$ 22,904	$ 29,959	$ 70,595	$ 91,361
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