Document And Entity Information	9 Months Ended
	Jun. 30, 2012	Jul. 31, 2012
Document And Entity Information [Abstract]
Entity Registrant Name	ATWOOD OCEANICS INC
Entity Central Index Key	0000008411
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		65,364,043
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2012
Trading Symbol	atw