Property, Plant, and Equipment, Net (Narrative) (Details) (USD $) In Thousands, unless otherwise specified			6 Months Ended	3 Months Ended
Mar. 31, 2012	Sep. 30, 2011	Mar. 31, 2012 System Test Facility [Member] sqft	Mar. 31, 2012 Computer Equipment and Software [Member]
Size of system test facility, in square feet			48,000
Contruction in progress and other assets placed into service			$ 16,738	$ 16,166
Construction in progress	$ 33,847	$ 44,975	$ 5,247

Gross amount, at the balance sheet date, of long-lived assets under construction that include construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Name:	us-gaap_ConstructionInProgressGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant