Nature of Operations (Details)	9 Months Ended
	Sep. 30, 2012 rig item
Nature of Operations
Number of platform rigs actively marketed	40
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	521
Number of states in which oil, gas and geothermal land drilling operations are conducted	48
Joint Venture in Saudi Arabia
Nature of Operations
Ownership percentage	51.00%
Number of rigs actively markets in joint venture	9
Other equity method investments | Minimum
Nature of Operations
Ownership percentage	49.00%
Other equity method investments | Maximum company's ownership interest in oil and gas joint venture
Nature of Operations
Ownership percentage	50.00%
U.S.
Nature of Operations
Number of rigs marketing for land well-servicing and workover work	431
Canada
Nature of Operations
Number of rigs marketing for land well-servicing and workover work	176