Segment Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012
Segment reporting, asset reconciling
Total assets	$ 6,197,611		$ 6,197,611		$ 5,721,085
Revenues from external customers
Total operating revenue	840,197	819,785	2,523,078	2,322,355
Continuing operations
Segment reporting, asset reconciling
Total assets	6,193,151		6,193,151		5,713,466
Discontinuing operations
Segment reporting, asset reconciling
Total assets	4,460		4,460		7,619
United States
Revenues from external customers
Total operating revenue	750,644	751,387	2,249,764	2,113,479
Colombia
Revenues from external customers
Total operating revenue	22,856	19,046	74,330	58,371
Ecuador
Revenues from external customers
Total operating revenue	15,993	15,178	48,234	41,753
Argentina
Revenues from external customers
Total operating revenue	18,943	13,845	50,111	37,953
Other Foreign
Revenues from external customers
Total operating revenue	31,761	20,329	100,639	70,799
Contract Drilling
Revenues from external customers
Total operating revenue	836,653	815,885	2,513,075	2,311,504
U.S. Land
Segment reporting, asset reconciling
Total assets	4,705,254		4,705,254		4,422,297
Revenues from external customers
Total operating revenue	695,816	706,786	2,077,556	1,983,369
Offshore
Segment reporting, asset reconciling
Total assets	155,197		155,197		160,135
Revenues from external customers
Total operating revenue	53,859	41,617	167,182	135,830
International Land
Segment reporting, asset reconciling
Total assets	458,702		458,702		467,538
Revenues from external customers
Total operating revenue	86,978	67,482	268,337	192,305
Other
Segment reporting, asset reconciling
Total assets	32,047		32,047		33,539
Revenues from external customers
Total operating revenue	3,544	3,900	10,003	10,851
Reportable and other
Segment reporting, asset reconciling
Total assets	5,351,200		5,351,200		5,083,509
Revenues from external customers
Total operating revenue	840,197	819,785	2,523,078	2,322,355
Investments and corporate operations
Segment reporting, asset reconciling
Total assets	$ 841,951		$ 841,951		$ 629,957