Discontinued operations (Tables) - Summary of Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Discontinued Operations and Disposal Groups [Abstract]
Revenue	$ 0	$ 15	$ 0	$ 30
Operating expenses	0	9	0	25
Gain on sale before taxes	0	0	0	0
Income before income taxes	0	6	0	5
Permanent tax benefit	0	0	0	0
Provision for income taxes	0	(2)	0	(2)
Income from discontinued operations	$ 0	$ 4	$ 0	$ 3

Overall income (loss) from a disposal group that is classified as a component of the entity, before income tax, reported as a separate component of income before extraordinary items. Includes the following (before income tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Amount of tax expense or benefit on gain (loss), not previously recognized, resulting from the sale of a business component.

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- Definition

Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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