Fair Value of Financial Instruments (Tables)

6 Months Ended

12 Months Ended

Mar. 31, 2013

Sep. 30, 2012

Fair Value of Financial Instruments

Summary of assets and liabilities measured and recorded at fair value on Balance Sheet on a recurring basis

	March 31, 2013
	Level 1		Level 2		Level 3		Total
Assets
Cash equivalents	$	115,214	$	—	$	—	$	115,214
Current derivative assets	—		2,827		—		2,827
Noncurrent derivative assets	—		5,303		—		5,303
Total assets measured at fair value	$	115,214	$	8,130	$	—	$	123,344
Liabilities
Current derivative liabilities	$	—	$	6,809	$	—	$	6,809
Noncurrent derivative liabilities	—		7,170		—		7,170
Contingent consideration to Seller of NEK	—		—		11,684		11,684
Total liabilities measured at fair value	$	—	$	13,979	$	11,684	$	25,663

	September 30, 2012
	Level 1		Level 2		Level 3		Total
Assets
Cash equivalents	$	171,300	$	—	$	—	$	171,300
Current derivative assets	—		3,779		—		3,779
Noncurrent derivative assets	—		3,713		—		3,713
Total assets measured at fair value	$	171,300	$	7,492	$	—	$	178,792
Liabilities
Current derivative liabilities	$	—	$	6,839	$	—	$	6,839
Noncurrent derivative liabilities	—		6,498		—		6,498
Total liabilities measured at fair value	$	—	$	13,337	$	—	$	13,337

The following table presents assets and liabilities measured and recorded at fair value on our balance sheets on a recurring basis (in thousands):

	September 30, 2012						September 30, 2011						September 30, 2010						September 30, 2009
	Level 1		Level 2		Total		Level 1		Level 2		Total		Level 1		Level 2		Total		Level 1		Level 2		Total
Assets
Cash equivalents	$	171,300	$	—	$	171,300	$	266,842	$	—	$	266,842	$	129,756	$	—	$	129,756	$	178,893	$	—	$	178,893
Short-term investments—U.S. government agency securities		—		—		—		—		—		—		—		36,000		36,000		—		8,127		8,127
Short-term investments—tax exempt bonds		—		—		—		—		25,829		25,829		—		48,081		48,081		—		—		—
Current derivative assets		—		3,779		3,779		—		7,466		7,466		—		11,428		11,428		—		18,106		18,106
Non-current derivative assets		—		3,713		3,713		—		—		—		—		—		—		—		—		—
Total assets measured at fair value		171,300		7,492		178,792		266,842		33,295		300,137		129,756		95,509		225,265		178,893		26,233		205,126
Liabilities
Current derivative liabilities		—		6,839		6,839		—		7,522		7,522		—		3,193		3,193		—		17,933		17,933
Non-current derivative liabilities		—		6,498		6,498		—		6,164		6,164		—		4,748		4,748		—		—		—
Total liabilities measured at fair value	$	—	$	13,337	$	13,337	$	—	$	13,686	$	13,686	$	—	$	7,941	$	7,941	$	—	$	17,933	$	17,933