Product Warranties (Details) (USD $)	3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended				6 Months Ended	9 Months Ended			12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Sep. 30, 2011 Power supply devices installment	Jun. 30, 2012 Power supply devices	Dec. 31, 2011 Power supply devices	Sep. 30, 2011 Power supply devices	Jun. 30, 2011 Power supply devices	Jun. 30, 2011 Power supply devices	Jun. 30, 2012 Power supply devices	Sep. 30, 2011 Other assets Power supply devices	Jun. 30, 2011 Other assets Power supply devices	Dec. 31, 2011 Cost of goods sold	Sep. 30, 2011 Cost of goods sold Power supply devices
Product Liability Contingency [Line Items]
Standard product warranty term			3 years
Reimbursements from suppliers										$ 1,000,000				$ 1,200,000
Previously recognized warranty liability							2,700,000		1,300,000
Estimated product warranty liability					1,500,000	3,500,000		1,500,000			3,500,000
Reimbursement receivable, warranty costs												500,000	1,300,000
Settlement agreement, cash consideration					1,200,000			1,200,000
Loss contingency, proceeds received											600,000
Potential reimbursement, warranty costs								500,000
Settlement amount expected to receive					600,000			600,000
Number of quarterly installments receivable					4
Commencement of installments, period from date of settlement agreement					P3M
Period of product rebates/price concessions under settlement agreement					39 months
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance, beginning of period	6,930,000	881,000	6,871,000	982,000			2,800,000				2,800,000				5,500,000
Charges to operations	48,000	1,781,000	416,000	2,265,000
Deductions for costs incurred	(2,199,000)	(506,000)	(2,508,000)	(1,091,000)		(2,000,000)
Balance, end of period	$ 4,779,000	$ 2,156,000	$ 4,779,000	$ 2,156,000	$ 2,800,000		$ 5,500,000	$ 2,800,000							$ 5,500,000