Segment Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Sep. 30, 2011
Segment reporting, asset reconciling
Total assets	$ 5,518,301		$ 5,518,301		$ 5,003,891
Revenues from external customers
Total operating revenue	819,785	644,095	2,322,355	1,843,143
Investments and corporate operations
Segment reporting, asset reconciling
Total assets	620,406		620,406		757,101
Continuing operations
Segment reporting, asset reconciling
Total assets	5,510,723		5,510,723		4,996,362
Discontinuing operations
Segment reporting, asset reconciling
Total assets	7,578		7,578		7,529
United States
Revenues from external customers
Total operating revenue	751,387	587,307	2,113,479	1,641,929
Colombia
Revenues from external customers
Total operating revenue	19,046	16,797	58,371	55,372
Ecuador
Revenues from external customers
Total operating revenue	15,178	9,105	41,753	29,222
Argentina
Revenues from external customers
Total operating revenue	13,845	9,121	37,953	34,019
Other Foreign
Revenues from external customers
Total operating revenue	20,329	21,765	70,799	82,601
Contract Drilling
Segment reporting, asset reconciling
Total assets	4,890,317		4,890,317		4,239,261
Revenues from external customers
Total operating revenue	815,885	639,992	2,311,504	1,831,360
U.S. Land
Segment reporting, asset reconciling
Total assets	4,288,724		4,288,724		3,719,387
Revenues from external customers
Total operating revenue	706,786	539,372	1,983,369	1,511,649
Offshore
Segment reporting, asset reconciling
Total assets	145,921		145,921		151,656
Revenues from external customers
Total operating revenue	41,617	54,569	135,830	150,022
International Land
Segment reporting, asset reconciling
Total assets	421,331		421,331		333,142
Revenues from external customers
Total operating revenue	67,482	46,051	192,305	169,689
Other.
Segment reporting, asset reconciling
Total assets	34,341		34,341		35,076
Revenues from external customers
Total operating revenue	3,900	4,103	10,851	11,783
Reportable and other
Revenues from external customers
Total operating revenue	$ 819,785	$ 644,095	$ 2,322,355	$ 1,843,143