Nature of Operations (Details)	12 Months Ended
	Dec. 31, 2012 rig item
Nature of Operations
Number of platform rigs actively marketed	36
Number of jack-up rigs actively marketed	12
Number of barge rigs actively marketed	4
Number of hydraulic horsepower pressure pumping services in key basins throughout United States and Canada	805,000
Number of major business lines	2
Nature of operations
Number of actively marketed land drilling rigs	474
Number of states in which oil, gas and geothermal land drilling operations are conducted	48
Minimum number of countries in which oil and gas land drilling operations are conducted	20
Joint Venture in Saudi Arabia
Nature of Operations
Ownership percentage	51.00%
Number of rigs actively markets in joint venture	9
U.S.
Nature of Operations
Number of rigs marketing for land well-servicing and workover work	442
Canada
Nature of Operations
Number of rigs marketing for land well-servicing and workover work	106