Fair Value of Financial Instruments (Details) (USD $)	9 Months Ended	12 Months Ended		0 Months Ended
	Jun. 30, 2013	Sep. 30, 2012	Dec. 31, 2012 NEK Special Programs Group LLC (NEK)	Dec. 14, 2012 NEK Special Programs Group LLC (NEK) Minimum	Dec. 14, 2012 NEK Special Programs Group LLC (NEK) Maximum	Jun. 30, 2013 Assets and liabilities measured at fair value on a recurring basis Level 1	Sep. 30, 2012 Assets and liabilities measured at fair value on a recurring basis Level 1	Jun. 30, 2013 Assets and liabilities measured at fair value on a recurring basis Level 2	Sep. 30, 2012 Assets and liabilities measured at fair value on a recurring basis Level 2	Jun. 30, 2013 Assets and liabilities measured at fair value on a recurring basis Level 3	Jun. 30, 2013 Assets and liabilities measured at fair value on a recurring basis Total	Sep. 30, 2012 Assets and liabilities measured at fair value on a recurring basis Total
Fair Value of Financial Instruments
Change in the fair value of the contingent consideration		$ 0
Contingent consideration expense	0
Assets and liabilities measured at fair value on a recurring basis
Period within which contingent consideration will be paid				6 months	9 months
Assets
Cash equivalents						137,981,000	171,300,000				137,981,000	171,300,000
Marketable securities						4,049,000					4,049,000
Current derivative assets								3,918,000	3,779,000		3,918,000	3,779,000
Non-current derivative assets								6,634,000	3,713,000		6,634,000	3,713,000
Total assets measured at fair value						142,030,000	171,300,000	10,552,000	7,492,000		152,582,000	178,792,000
Liabilities
Current derivative liabilities								3,469,000	6,839,000		3,469,000	6,839,000
Non-current derivative liabilities								5,694,000	6,498,000		5,694,000	6,498,000
Fair value of additional contingent cash consideration			11,100,000							11,104,000	11,104,000
Total liabilities measured at fair value								9,163,000	13,337,000	11,104,000	20,267,000	13,337,000
Debt instruments
Estimated fair value of long-term debt	96,600,000	12,500,000
Carrying value of long-term debt	$ 102,900,000	$ 11,500,000