Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Comprehensive Income (Loss) [Abstract]
Net income (loss), as reported	$ (4,071)	$ 7,060	$ (11,234)	$ 19,546
Foreign currency translation adjustment	(3,851)	1,446	(5,380)	3,905
Comprehensive income (loss)	(7,922)	8,506	(16,614)	23,451
Comprehensive loss attributable to noncontrolling interest	1,106	238	2,314	261
Comprehensive income (loss) attributable to Amtech Systems, Inc.	$ (6,816)	$ 8,744	$ (14,300)	$ 23,712